Wcd system validating detected cardiac arrhythmias thoroughly so as to not sound loudly due to some quickly self-terminating cardiac arrhythmias

ABSTRACT

A wearable cardioverter defibrillator (“WCD”) system may output a loud sound after detecting and validating a shockable cardiac arrhythmia. In such embodiments, however, the WCD system might not sound a loud alarm before validating the arrhythmia thoroughly, i.e. for a longer time, thus giving the arrhythmia a further chance to self-terminate. The WCD system may thus detect more robustly the cardiac arrhythmias that do not self-terminate quickly. Such arrhythmias that self-terminate quickly may occur from likely harmless events occurring multiple times in the daily life of the patient, such as the patient becoming “winded” from climbing stairs. In embodiments the WCD system may notify the patient only discreetly, or even not at all. The lack of sounding such a loud alarm responsive to such events reduces the overall number of times in which the patient experiences unwanted attention by others, embarrassment, loss of privacy and dignity, and so on.

CROSS REFERENCE TO RELATED PATENT APPLICATIONS

This patent application claims the benefit of U.S. Provisional patentapplication Ser. No. 62/425,071 filed on Dec. 15, 2016, and this patentapplication is further a Continuation-In-Part of co-pending U.S. patentapplication Ser. No. 14/941,592 filed on Nov. 14, 2015, the applicationSer. No. 14/941,592 being a Continuation-In-Part of U.S. patentapplication No. 14/461,670 filed on Aug. 18, 2014, now abandoned, theapplication Ser. No. 14/941,592 further being a Continuation-In-Part ofU.S. patent application Ser. No. 14/743,882 filed on Jun. 18, 2015, nowissued as U.S. Pat. No. 9,592,403 on Mar. 14, 2017, which in turn is acontinuation of U.S. patent application Ser. No. 14/189,789 filed onFeb. 25, 2014, now issued as U.S. Pat. No. 9,089,685 on Jul. 28, 2015,which in turn claims the benefit of provisional 61/769,098 filed on Feb.25, 2013.

BACKGROUND

When people suffer from some types of heart arrhythmias, the result maybe that blood flow to various parts of the body is reduced. Somearrhythmias may even result in a sudden cardiac arrest (SCA). SCA canlead to death very quickly, e.g. within 10 minutes, unless treated inthe interim.

Some people have an increased risk of SCA. People at a higher riskinclude patients who have had a heart attack, or a prior SCA episode. Afrequent recommendation is for these people to receive an implantablecardioverter defibrillator (“ICD”). The ICD is surgically implanted inthe chest, and continuously monitors the patient's electrocardiogram(“ECG”). If certain types of heart arrhythmias are detected, then theICD delivers an electric shock through the heart.

After being identified as having an increased risk of an SCA, and beforereceiving an ICD, these people are sometimes given a wearablecardioverter defibrillator (“WCD”) system. (Earlier versions of suchsystems were called wearable cardiac defibrillator systems.) A WCDsystem typically includes a harness, vest, or other garment that thepatient is to wear. The WCD system includes a defibrillator andelectrodes, coupled to the harness, vest, or other garment. When thepatient wears the WCD system, the external electrodes may then make goodelectrical contact with the patient's skin, and therefore can helpdetermine the patient's ECG. If a shockable heart arrhythmia isdetected, then the defibrillator delivers the appropriate electric shockthrough the patient's body, and thus through the heart.

BRIEF SUMMARY

The present description gives instances of wearable cardioverterdefibrillator (“WCD”) systems, storage media that store programs, andmethods, the use of which may help overcome problems and limitations ofthe prior art.

In some embodiments, a wearable cardioverter defibrillator (“WCD”)system may output a loud sound after detecting and validating ashockable cardiac arrhythmia. In such embodiments, however, the WCDsystem might not sound a loud alarm before validating the arrhythmiathoroughly, i.e. for a longer time, thus giving the arrhythmia a furtherchance to self-terminate. As such, the WCD system may detect morerobustly the cardiac arrhythmias that do not self-terminate quickly.

In some embodiments, a wearable cardioverter defibrillator (“WCD”)system may output a loud sound after detecting and validating ashockable cardiac arrhythmia. If the cardiac arrhythmia self-terminatesrelatively quickly, however, the WCD system might transmit data from thecardiac arrhythmia for analysis, without sounding loudly due to thecardiac arrhythmia.

In some embodiments, a wearable cardioverter defibrillator (“WCD”)system may output a loud sound after detecting and validating ashockable cardiac arrhythmia. If the cardiac arrhythmia self-terminatesrelatively quickly, however, the WCD system might store data from thecardiac arrhythmia for later analysis, without sounding loudly due tothe cardiac arrhythmia.

In some embodiments, a wearable cardioverter defibrillator (“WCD”)system may output an audible sound after detecting and validating ashockable cardiac arrhythmia. Before validating, however, the WCD systemmay wait discreetly for the detected cardiac arrhythmia toself-terminate relatively quickly, without outputting such a sound untilthen.

In some embodiments, a wearable cardioverter defibrillator (“WCD”)system may output a loud sound after detecting and validating ashockable cardiac arrhythmia. Before validating, however, the WCD systemmay wait discreetly for the detected cardiac arrhythmia toself-terminate relatively quickly, without outputting such a sound untilthen.

Such arrhythmias that self-terminate quickly may occur from likelyharmless events, possibly occurring multiple times in the daily life ofthe patient. For example, the patient may experience a brief episode oftachycardia, or become “winded”, from climbing stairs. In some of theseembodiments, the WCD system may wait for such an arrhythmia event toterminate, and notify the patient only discreetly, or even not at all.The lack of sounding such a loud alarm responsive to such events reducesthe overall number of times in which the patient experiences unwantedattention by others, embarrassment, loss of privacy and dignity, and soon.

These and other features and advantages of this description will becomemore readily apparent from the Detailed Description, which proceeds withreference to the associated drawings in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of components of a sample wearable cardioverterdefibrillator (“WCD”) system, made according to embodiments.

FIG. 2 is a diagram showing sample components of an externaldefibrillator, such as the one belonging in the system of FIG. 1, andwhich is made according to embodiments.

FIG. 3A is a rendering of diagram in a publication that describescharacteristics of a WCD system in the prior art, with annotations.

FIG. 3B shows a magnification of a section of the prior art diagram ofFIG. 3A, with further annotations along an added time axis.

FIG. 3C shows a magnification of a section of the prior art diagram ofFIG. 3A, with further annotations along an added time axis.

FIG. 4 is a flowchart for illustrating methods according to embodiments.

FIG. 5 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 4.

FIG. 6 is a flowchart for illustrating methods according to embodiments.

FIG. 7 is a flowchart for illustrating methods according to embodiments.

FIG. 8 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 7.

FIG. 9 is a flowchart for illustrating methods according to embodiments.

FIG. 10 is a diagram illustrating how it may be determined that adetected arrhythmia is of a first type according to embodiments.

FIG. 11 is a diagram illustrating how it may be determined that adetected arrhythmia is of a second type according to embodiments.

FIG. 12 is a diagram illustrating how it may be determined whether adetected arrhythmia is of a first type or of a second type according toembodiments.

FIG. 13 is a flowchart for illustrating methods of how a cardiacarrhythmia may be confirmed according to embodiments.

FIG. 14 is a flowchart for illustrating methods according toembodiments.

FIG. 15 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 14.

FIG. 16 is a flowchart for illustrating methods according toembodiments.

FIG. 17 is a flowchart for illustrating methods according toembodiments.

FIG. 18 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 17.

FIG. 19 is a flowchart for illustrating methods according toembodiments.

FIG. 20 is a flowchart for illustrating methods according toembodiments, along with an operating example for sample values V1, V2,V3 & V4.

FIG. 21 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 20.

FIG. 22 is a table showing possible results of operations responsive toa series of values derived from a physiological input of the operatingexample of FIG. 20, according to embodiments.

FIG. 23 is a table showing possible results of operations responsive toa series of values derived from a physiological input of the operatingexample of FIG. 20, according to embodiments.

FIG. 24 is a flowchart for illustrating methods according toembodiments.

FIG. 25 is a time diagram of a sample series of events that may resultfrom methods of the flowchart of FIG. 24.

DETAILED DESCRIPTION

As has been mentioned, the present description is about wearablecardioverter defibrillator (“WCD”) systems, storage media that storeprograms, and methods. Embodiments are now described in more detail.

A wearable cardioverter defibrillator (“WCD”) system made according toembodiments has a number of components. These components can be providedseparately as modules that can be interconnected, or can be combinedwith other components, etc.

FIG. 1 depicts a patient 82. Patient 82 may also be referred to as aperson and/or wearer, since that patient wears components of the WCDsystem.

FIG. 1 also depicts components of a WCD system made according toembodiments. One such component is a support structure 170 that iswearable by patient 82. It will be understood that support structure 170is shown only generically in FIG. 1, and in fact partly conceptually.FIG. 1 is provided merely to illustrate concepts about support structure170, and is not to be construed as limiting how support structure 170 isimplemented, or how it is worn.

Support structure 170 can be implemented in many different ways. Forexample, it can be implemented in a single component or a combination ofmultiple components. In embodiments, support structure 170 could includea vest, a half-vest, a garment, etc. In such embodiments such items canbe worn similarly to parallel articles of clothing. In embodiments,support structure 170 could include a harness, one or more belts orstraps, etc. In such embodiments, such items can be worn by around thetorso, hips, over the shoulder, etc. In embodiments, support structure170 can include a container or housing, which can even be waterproof. Insuch embodiments, the support structure can be worn by being attached tothe patient by adhesive material, for example as shown in U.S. Pat. No.8,024,037. Support structure 170 can even be implemented as describedfor the support structure of U.S. Pat. App. No. U.S. 2017/0056682A1,which is incorporated herein by reference. Of course, in suchembodiments, a person skilled in the art will recognize that additionalcomponents of the WCD system can be in the housing of a supportstructure instead of attached externally to the support structure, forexample as described in the document incorporated by reference. Therecan be other examples.

A WCD system according to embodiments is configured to defibrillate apatient who is wearing it, by delivering an electrical charge to thepatient's body in the form of an electric shock delivered in one or morepulses. FIG. 1 shows a sample external defibrillator 100, and sampledefibrillation electrodes 104, 108, which are coupled to externaldefibrillator 100 via electrode leads 105. Defibrillator 100 anddefibrillation electrodes 104, 108 are coupled to support structure 170.As such, many of the components of defibrillator 100 can be thereforecoupled to support structure 170. When defibrillation electrodes 104,108 make good electrical contact with the body of patient 82,defibrillator 100 can administer, via electrodes 104, 108, a brief,strong electric pulse 111 through the body. Pulse 111, also known as adefibrillation shock or therapy shock, is intended to go through andrestart heart 85, in an effort to save the life of patient 82. Pulse 111can further include one or more pacing pulses, and so on.

A prior art defibrillator typically decides whether to defibrillate ornot based on an ECG signal of the patient. However, defibrillator 100can defibrillate, or not defibrillate, also based on other inputs.

The WCD system may optionally include an outside monitoring device 180.Device 180 is called an “outside” device because it is provided as astandalone device, for example not within the housing of defibrillator100. Device 180 can be configured to monitor at least one localparameter. A local parameter can be a parameter of patient 82, or aparameter of the WCD system, or a parameter of the environment, as willbe described later in this document.

Optionally, device 180 is physically coupled to support structure 170.In addition, device 180 can be communicatively coupled with othercomponents, which are coupled to support structure 170. Suchcommunication can be implemented by a communication module, as will bedeemed applicable by a person skilled in the art in view of thisdisclosure.

FIG. 2 is a diagram showing components of an external defibrillator 200,made according to embodiments. These components can be, for example,included in external defibrillator 100 of FIG. 1. The components shownin FIG. 2 can be provided in a housing 201, which is also known ascasing 201.

External defibrillator 200 is intended for a patient who would bewearing it, such as patient 82 of FIG. 1. Defibrillator 200 may furtherinclude a user interface 270 for a user 282. User 282 can be patient 82,also known as wearer 82. Or user 282 can be a local rescuer at thescene, such as a bystander who might offer assistance, or a trainedperson. Or, user 282 might be a remotely located trained caregiver incommunication with the WCD system.

User interface 270 can be made in any number of ways. User interface 270may include output devices, which can be visual, audible or tactile, forcommunicating to a user. For example, an output device can be a light,or a screen to display what is detected and measured, and provide visualfeedback to rescuer 282 for their resuscitation attempts, and so on.Other output devices can be speakers 271, 272, etc. Such a speaker canbe any device that can output a sound, whether speech or not. Forexample, speaker 271 can be configured to issue voice prompts, etc.Speaker 272 can be an electronic audible alarm such as a siren, asonalert, etc. Sounds, lights, images, vibrations, and anything that canbe perceived by user 282 can also be called human-perceptibleindications. In diagrams that accompany the present description, a“human-perceptible indication” may be abbreviated as “HPI”. Userinterface 270 may also include input devices for receiving inputs fromusers. Such input devices may additionally include various controls,such as pushbuttons, keyboards, touchscreens, a microphone, and so on.An input device can be a cancel switch, which is sometimes called a“live-man” switch and a divert button. In some embodiments, actuatingthe cancel switch can prevent the impending delivery of a shock.

Defibrillator 200 may include an internal monitoring device 281. Device281 is called an “internal” device because it is incorporated withinhousing 201. Monitoring device 281 can monitor patient parameters,patient physiological parameters, system parameters and/or environmentalparameters, all of which can be called patient data. In other words,internal monitoring device 281 can be complementary or an alternative tooutside monitoring device 180 of FIG. 1. Allocating which of the systemparameters are to be monitored by which monitoring device can be doneaccording to design considerations.

Patient physiological parameters include, for example, thosephysiological parameters that can be of any help in detecting by thewearable defibrillation system whether the patient is in need of ashock, plus optionally their medical history and/or event history.Examples of such parameters include the patient's ECG, blood oxygenlevel, blood flow, blood pressure, blood perfusion, pulsatile change inlight transmission or reflection properties of perfused tissue, heartsounds, heart wall motion, breathing sounds and pulse. Accordingly, themonitoring device could include a perfusion sensor, a pulse oximeter, aDoppler device for detecting blood flow, a cuff for detecting bloodpressure, an optical sensor, illumination detectors and perhaps sourcesfor detecting color change in tissue, a motion sensor, a device that candetect heart wall movement, a sound sensor, a device with a microphone,an SpO2 sensor, and so on. Pulse detection is taught at least inPhysio-Control's U.S. Pat. No. 8,135,462, which is hereby incorporatedby reference in its entirety. In addition, a person skilled in the artmay implement other ways of performing pulse detection.

In some embodiments, the local parameter is a trend that can be detectedin a monitored physiological parameter of patient 82. A trend can bedetected by comparing values of parameters at different times.Parameters whose detected trends can particularly help a cardiacrehabilitation program include: a) cardiac function (e.g. ejectionfraction, stroke volume, cardiac output, etc.); b) heart ratevariability at rest or during exercise; c) heart rate profile duringexercise and measurement of activity vigor, such as from the profile ofan accelerometer signal and informed from adaptive rate pacemakertechnology; d) heart rate trending; e) perfusion, such as from SpO2 orCO2; f) respiratory function, respiratory rate, etc.; g) motion, levelof activity; and so on. Once a trend is detected, it can be storedand/or reported via a communication link, along perhaps with a warning.From the report, a physician monitoring the progress of patient 82 willknow about a condition that is either not improving or deteriorating.

Patient state parameters include recorded aspects of patient 82, such asmotion, posture, whether they have spoken recently plus maybe also whatthey said, and so on, plus optionally the history of these parameters.Or, one of these monitoring devices could include a location sensor suchas a global positioning system (“GPS”) location sensor. Such a sensorcan detect the location, plus a speed can be detected as a rate ofchange of location over time. Many motion detectors output a motionsignal that is indicative of the motion of the detector, and thus of thepatient's body. Patient state parameters can be very helpful innarrowing down the determination of whether SCA is indeed taking place.

A WCD system made according to embodiments may include a motiondetector. In embodiments, a motion detector can be implemented withinmonitoring device 180 or monitoring device 281. Such a motion detectorcan be configured to detect a motion event. In response, the motiondetector may render or generate from the detected motion event a motiondetection input that can be received by a subsequent device orfunctionality. A motion event can be defined as is convenient, forexample a change in motion from a baseline motion or rest, etc. Such amotion detector can be made in many ways as is known in the art, forexample by using an accelerometer.

System parameters of a WCD system can include system identification,battery status, system date and time, reports of self-testing, recordsof data entered, records of episodes and intervention, and so on.

Environmental parameters can include ambient temperature and pressure. Ahumidity sensor may provide information as to whether it is likelyraining. Presumed patient location could also be considered anenvironmental parameter. The patient location could be presumed ifmonitoring device 180 or 281 includes a GPS location sensor as per theabove.

Defibrillator 200 typically includes a defibrillation port 210, such asa socket in housing 201. Defibrillation port 210 includes electricalnodes 214, 218. Leads of defibrillation electrodes 204, 208, such asleads 105 of FIG. 1, can be plugged into defibrillation port 210, so asto make electrical contact with nodes 214, 218, respectively. It is alsopossible that defibrillation electrodes 204, 208 are connectedcontinuously to defibrillation port 210, instead. Either way,defibrillation port 210 can be used for guiding, via electrodes, to thewearer the electrical charge that has been stored in energy storagemodule 250. The electric charge will be the shock for defibrillation,pacing, and so on.

Defibrillator 200 may optionally also have an ECG port 219 in housing201, for plugging in sensing electrodes 209, which are also known as ECGelectrodes and ECG leads. It is also possible that sensing electrodes209 can be connected continuously to ECG port 219, instead. Sensingelectrodes 209 can help sense an ECG signal, e.g. a 12-lead signal, or asignal from a different number of leads, especially if they make goodelectrical contact with the body of the patient. Sensing electrodes 209can be attached to the inside of support structure 170 for making goodelectrical contact with the patient, similarly as defibrillationelectrodes 204, 208.

Optionally a WCD system according to embodiments also includes a fluidthat it can deploy automatically between the electrodes and the patientskin. The fluid can be conductive, such as by including an electrolyte,for making a better electrical contact between the electrode and theskin. Electrically speaking, when the fluid is deployed, the electricalimpedance between the electrode and the skin is reduced. Mechanicallyspeaking, the fluid may be in the form of a low-viscosity gel, so thatit does not flow away, after it has been deployed. The fluid can be usedfor both defibrillation electrodes 204, 208, and sensing electrodes 209.

The fluid may be initially stored in a fluid reservoir, not shown inFIG. 2, which can be coupled to the support structure. In addition, aWCD system according to embodiments further includes a fluid deployingmechanism 274. Fluid deploying mechanism 274 can be configured to causeat least some of the fluid to be released from the reservoir, and bedeployed near one or both of the patient locations, to which theelectrodes are configured to be attached to the patient. In someembodiments, fluid deploying mechanism 274 is activated responsive toreceiving activation signal AS from processor 230, prior to theelectrical discharge.

Defibrillator 200 also includes a measurement circuit 220. Measurementcircuit 220 receives physiological signals of the patient from ECG port219, if provided. Even if defibrillator 200 lacks ECG port 219,measurement circuit 220 can obtain physiological signals through nodes214, 218 instead, when defibrillation electrodes 204, 208 are attachedto the patient. In these cases, the patient's ECG signal can be sensedas a voltage difference between electrodes 204, 208. Plus, impedancebetween electrodes 204, 208 and/or the connections of ECG port 219 canbe sensed. Sensing the impedance can be useful for detecting, amongother things, whether these electrodes 204, 208 and/or sensingelectrodes 209 are not making good electrical contact with the patient'sbody. These patient physiological signals can be sensed, when available.Measurement circuit 220 can then render or generate information aboutthem as physiological inputs, data, other signals, etc. More strictlyspeaking, the information rendered by measurement circuit 220 is outputfrom it, but this information can be called an input because it isreceived by a subsequent device or functionality as an input.

Defibrillator 200 also includes a processor 230. Processor 230 may beimplemented in any number of ways. Such ways include, by way of exampleand not of limitation, digital and/or analog processors such asmicroprocessors and digital signal processors (“DSP”s); controllers suchas microcontrollers; software running in a machine; programmablecircuits such as field programmable gate arrays (“FPGA”s),field-programmable analog arrays (“FPAA”s), programmable logic devices(“PLD”s), application specific integrated circuits (“ASIC”s), anycombination of one or more of these, and so on.

Processor 230 can be considered to have a number of modules. One suchmodule can be a detection module 232. Detection module 232 can include aventricular fibrillation (“VF”) detector. The patient's sensed ECG frommeasurement circuit 220, which can be available as physiological inputs,data, or other signals, may be used by the VF detector to determinewhether the patient is experiencing VF. Detecting VF is useful, becauseVF results in SCA. Detection module 232 can also include a ventriculartachycardia (“VT”) detector, and so on.

Another such module in processor 230 can be an advice module 234, whichgenerates advice for what to do. The advice can be based on outputs ofdetection module 232. There can be many types of advice according toembodiments. In some embodiments, the advice is a shock/no shockdetermination that processor 230 can make, for example via advice module234. The shock/no shock determination can be made by executing a storedShock Advisory Algorithm. A Shock Advisory Algorithm can make a shock/noshock determination from one or more of ECG signals that are capturedaccording to embodiments, and determining whether a shock criterion ismet. The determination can be made from a rhythm analysis of thecaptured ECG signal or otherwise.

In some embodiments, when the decision is to shock, an electrical chargeis delivered to the patient. Delivering the electrical charge is alsoknown as discharging. Shocking can be for defibrillation, pacing, and soon.

Processor 230 can include additional modules, such as other module 236,for other functions. In addition, if internal monitoring device 281 isindeed provided, it may be operated in part by processor 230, etc.

Defibrillator 200 optionally further includes a memory 238, which canwork together with processor 230. Memory 238 may be implemented in anynumber of ways. Such ways include, by way of example and not oflimitation, volatile memories, nonvolatile memories (“NVM”), read-onlymemories (“ROM”), random access memories (“RAM”), magnetic disk storagemedia, optical storage media, smart cards, flash memory devices, anycombination of these, and so on. Memory 238 is thus a non-transitorystorage medium. Memory 238, if provided, can include programs forprocessor 230, which processor 230 may be able to read and execute. Moreparticularly, the programs can include sets of instructions in the formof code, which processor 230 may be able to execute upon reading.Executing is performed by physical manipulations of physical quantities,and may result in functions, processes, actions and/or methods to beperformed, and/or the processor to cause other devices or components orblocks to perform such functions, processes, actions and/or methods. Theprograms can be operational for the inherent needs of processor 230, andcan also include protocols and ways that decisions can be made by advicemodule 234. In addition, memory 238 can store prompts for user 282, ifthis user is a local rescuer. Moreover, memory 238 can store data. Thedata can include patient data, system data and environmental data, forexample as learned by internal monitoring device 281 and outsidemonitoring device 180. The data can be stored in memory 238 before it istransmitted out of defibrillator 200, or stored there after it isreceived by defibrillator 200.

Defibrillator 200 may also include a power source 240. To enableportability of defibrillator 200, power source 240 typically includes abattery. Such a battery is typically implemented as a battery pack,which can be rechargeable or not. Sometimes a combination is used ofrechargeable and non-rechargeable battery packs. Other embodiments ofpower source 240 can include an AC power override, for where AC powerwill be available, an energy storage capacitor, and so on. In someembodiments, power source 240 is controlled by processor 230.

Defibrillator 200 additionally includes an energy storage module 250,which can thus be coupled to the support structure of the WCD system.Module 250 is where some electrical energy is stored in the form of anelectrical charge, when preparing it for discharge to administer ashock. Module 250 can be charged from power source 240 (by receiving anelectrical charge) to the right amount of energy, as controlled byprocessor 230. In typical implementations, module 250 includes acapacitor 252, which can be a single capacitor or a system ofcapacitors, and so on. As described above, capacitor 252 can store theenergy in the form of an electrical charge, for delivering to thepatient.

Defibrillator 200 moreover includes a discharge circuit 255. When thedecision is to shock, processor 230 can be configured to controldischarge circuit 255 to discharge through the patient the electricalcharge stored in energy storage module 250. When so controlled, circuit255 can permit the energy stored in module 250 to be discharged to nodes214, 218, and from there also to defibrillation electrodes 204, 208, soas to cause a shock to be delivered to the patient while the supportstructure is worn by the patient. Circuit 255 can include one or moreswitches 257. Switches 257 can be made in a number of ways, such as byan H-bridge, and so on. Circuit 255 can also be controlled via userinterface 270.

Defibrillator 200 can optionally include a communication module 290, forestablishing one or more wired or wireless communication links withother devices of other entities, such as a remote assistance center,Emergency Medical Services (“EMS”), and so on. Module 290 may alsoinclude an antenna, portions of a processor, and other sub-components asmay be deemed necessary by a person skilled in the art. This way, dataand commands can be communicated, such as patient data, eventinformation, therapy attempted, CPR performance, system data,environmental data, and so on.

Defibrillator 200 can optionally include other components.

Returning to FIG. 1, in embodiments, one or more of the components ofthe shown WCD system have been customized for patient 82. Thiscustomization may include a number of aspects. For instance, supportstructure 170 can be fitted to the body of patient 82. For anotherinstance, baseline physiological parameters of patient 82 can bemeasured, such as the heart rate of patient 82 while resting, whilewalking, motion detector outputs while walking, etc. Such baselinephysiological parameters can be used to customize the WCD system, inorder to make its diagnoses more accurate, since bodies behavedifferently. For example, such parameters can be stored in a memory ofthe WCD system, and so on.

A programming interface can be made according to embodiments, whichreceives such measured baseline physiological parameters. Such aprogramming interface may input automatically in the WCD system thebaseline physiological parameters, along with other data.

FIG. 3A is a rendering of diagram in a publication that describescharacteristics of a WCD system in the prior art, with annotations addedin this document. In particular, FIG. 3A is labeled “FIG. 3” in thatpublication, which is: KLEIN Helmut U., GOLDENBERG Ilan & MOSS ArthurJ., Risk stratification for implantable cardioverter defibrillatortherapy: the role of the wearable cardioverter-defibrillator, EuropeanHeart Journal, 2013, pp. 1-14, doi:10.1093/eurheartj/eht167.

In FIG. 3A, the diagram of the prior art is designated in the rectangle301. It purports to describe the detection, treatment and alarm systemof a prior art WCD system. Attention is drawn to designated sections311, 321 of this diagram.

FIG. 3B shows a magnification of designated section 311 of the prior artdiagram of FIG. 3A, with further annotations along an added time axis312. Section 311 is characterized as detection time, shock delivery, andelectrocardiogram recording after shock delivery. In the added time axis312, certain events of section 311 have intercepts TA, TB, TD, TE, TF,TG, TH as shown, for easier reference.

In section 311, the time duration between TA and TD seems to be 30 secalong time axis 312. Section 311 seems to further show ECG data 360.This ECG data 360 seems to include QRS complexes 371, 372, 373, 391,392. Between times TB and TE there is an ECG portion 380. ECG portion380 seems to be a cardiac arrhythmia, since it seems to lack QRScomplexes, and to further be the cause for the alarms at TD and shockdelivery at time TF. In that case, the onset of the cardiac arrhythmiaof portion 380 takes place at time TB. By time TD, detection seems tohave happened. Judging from the fact that the duration from TA to TD is30 sec, the duration from TB to TD seems to be no more than 5 sec, ifthe time axis of that time diagram is to scale.

FIG. 3C shows a magnification of designated section 321 of the prior artdiagram of FIG. 3A, with further annotations along an added time axis322. Section 321 is characterized as the time sequence of alarms, etc.In particular, timeline 331 is characterized as ECG record, timeline 332is characterized as Validation period, timeline 333 is characterized asAlarms active, timeline 334 is characterized as Vibration alarm,timeline 335 is characterized as Siren, timeline 336 is characterized asLoud siren, timeline 337 is characterized as Bystander warning, timeline338 is characterized as Gel release, and timeline 339 is characterizedas Treatment shock.

In FIG. 3C, in the added time axis 322, certain events of section 321have intercepts TA, TC, TD, TF as shown, for easier reference. Some ofthese are the same time intercepts as those in time axis 312 of FIG. 3B.In addition, time intercept TB of FIG. 3B could be the same as timeintercept TC of FIG. 3C.

As mentioned above, embodiments of the invention include systems,processors and methods. The devices and/or systems mentioned in thisdocument perform functions, processes and/or methods. These functions,processes and/or methods may be implemented by one or more devices thatinclude logic circuitry. Such a device can be alternately called acomputer, and so on. It may be a standalone device or computer, such asa general purpose computer, or part of a device that has one or moreadditional functions. The logic circuitry may include a processor andnon-transitory computer-readable storage media, such as memories, of thetype described elsewhere in this document. Often, for the sake ofconvenience only, it is preferred to implement and describe a program asvarious interconnected distinct software modules or features. These,along with data are individually and also collectively known assoftware. In some instances, software is combined with hardware, in amix called firmware.

Moreover, methods and algorithms are described below. These methods andalgorithms are not necessarily inherently associated with any particularlogic device or other apparatus. Rather, they are advantageouslyimplemented by programs for use by a computing machine, such as ageneral-purpose computer, a special purpose computer, a microprocessor,a processor such as described elsewhere in this document, and so on.

This detailed description includes flowcharts, display images,algorithms, and symbolic representations of program operations within atleast one computer readable medium. An economy is achieved in that asingle set of flowcharts is used to describe both programs, such thatcan be executed by a processor, and also methods. So, while flowchartsdescribed methods in terms of boxes, they also concurrently describeprograms.

Methods are Now Described.

In some embodiments, a WCD system may output an openinghuman-perceptible indication, after detecting a shockable cardiacarrhythmia but before completing its analysis of the cardiac arrhythmia,for instance before validating the cardiac arrhythmia. Examples are nowdescribed.

FIG. 4 shows a flowchart 400 for describing methods according toembodiments. In addition, FIG. 5 is a time diagram of a sample series ofevents that may result from methods of the flowchart of FIG. 4. Ofcourse, a different series of events may result from the methods of theflowchart of FIG. 4. The events of FIG. 5 are shown along a time axis512, with intercepts that are not to scale. This portion of thisdescription proceeds by referring to both diagrams.

According to an operation 410 of FIG. 4, a patient physiological signalmay be monitored. The physiological signal can be the patient'selectrocardiogram (“ECG”), impedance, blood pressure, blood oxygensaturation, and so on. As mentioned previously, measurement circuit 220,or equivalently another transducer, may render a physiological inputfrom the monitored patient physiological signal. In FIG. 5, a timeline510 indicates that the physiological input starts being received at atime T1, by switching from a low value to a high value.

According to another operation 415 of FIG. 4, it is inquired whether acardiac arrhythmia is detected from the physiological input. It will beunderstood that this means a cardiac arrhythmia of interest, namely ashockable cardiac arrhythmia such as VF or VT. A difference between VFand VT is that the patient becomes unconscious very soon after VFstarts, while the patient may remain conscious throughout a VT episode,whether prolonged or not. As will be seen, embodiments may provide alonger confirmation period for VT than VF, which works well with thefact that VT sometimes self-terminates, while VF almost never does.

While at operation 415 no cardiac arrhythmia is being detected,execution returns to operation 410. This cardiac arrhythmia detection isshown in FIG. 5 along a timeline 515. There is no detection whiletimeline 515 has a low value. Detection may happen at time T2, at whichtime timeline 515 changes to a high value. At that time, detection mayhave been performed using inputs received earlier.

Returning to FIG. 4, if detection happens at operation 415 then,according to another operation 420, it can be determined whether or notthe cardiac arrhythmia is validated, for example according to avalidation criterion, meaning depending on whether or not the validationcriterion is met. For example, the validation criterion may include thatthe detected cardiac arrhythmia needs to be maintained for a thresholdvalidation time. The determination of whether or not the detectedcardiac arrhythmia meets the validation criterion can be made from oneof the physiological inputs. Operation 420 may need some time to beperformed.

In addition, according to another operation 472, an openinghuman-perceptible indication (“HPI”) may be caused to be outputresponsive to detecting the cardiac arrhythmia. This opening HPI may becaused to be output prior to completing the determination of operation420. Accordingly, the execution of operations 420, 472 may overlap intime at least in part. In the example of FIG. 5, timeline 520 showsvalidation being performed between times T2 and T5. Moreover, timeline572 shows an example of when the opening HPI is performed, and inparticular lasting between times T3 and T4. This opening HPI may becaused to be output at a time T3, which is prior to completing thedetermination of operation 420 at time T5.

It will be appreciated that, if the patient is having a VF episode, heor she might be unconscious and never perceive this opening HPI. On theother hand, if the patient's arrhythmia is a VT episode, he or she maywell be conscious and perceive their own arrhythmia.

In embodiments where this opening HPI is caused to be output prior tocompleting the determination of operation 420, the system might not knowyet whether it will shock the patient or not. Indeed, if the cardiacarrhythmia turns out to be a mild VT, and the patient is stillconscious, perhaps a shock will not be called for, eventually. A longerthreshold validation time may be called for, during which the VT mayself-terminate. As will be seen later in this document, in someembodiments where the VT is detected to self-terminate, no shock isadministered to the conscious patient. Of course, if the VT becomes fastVT and degenerates into VF, a shock will be needed.

Since this opening HPI is caused to be output prior to completing thedetermination of operation 420, in some embodiments this opening HPI mayfulfill the function of giving comfort and confidence to the patientthat their WCD system is working, while they do not have to do anything,such as immediately stopping what they are doing to frantically searchfor the cancel switch so as to avoid a shock while conscious. Nor willthey be embarrassed in front of others, if the opening HPI is discreet,and the cardiac arrhythmia eventually self-terminates. The opening HPImight give such comfort and confidence to a person who is having asustained episode of low-rate VT that causes them to feel uncomfortable(“crummy”), even though they don't need to be shocked. Such an episodemay self-terminate. In addition, the opening HPI might give such comfortand confidence to someone who learns news that excites them, such as bywatching a sports event. Such a person may experience a high-ratesupra-ventricular (SVT) rhythm that can make them feel crummy as well,even though they don't need to be shocked, either.

In order to give the patient this comfort and confidence, the openingHPI may communicate to the patient that at least some analysis will beperformed on the cardiac arrhythmia, for example to determine whether ornot it is validated. Such communicating may be explicit, for example bythe opening HPI including a voice message to the effect of “HAVEDETECTED ARRHYTHMIA OF YOUR HEART, AND NOW VALIDATING IT”. Alternately,an opening HPI can be more discreet, so that only the patient willperceive it. Such a more discreet opening HPI can be a tactile signallike a vibration, whose meaning the patient will have been trained tounderstand. For example, the opening HPI can be a group of threeconsecutive vibrations, perhaps each having the same duration. Ofcourse, the vibrations will have to be designed to be intense enough andprolonged enough to be perceptible by a patient above and beyond theirpossible VT, given that a VT is itself a vibration within their body.

In some instances, the determination of operation 420 may take longer,for example longer than 30 sec. In such cases, the opening HPI may beextended, for the patient's confidence in the WCD to be sustainedthrough the validation process. In some embodiments, the opening HPI maybe caused to be output for as long as operation 420 is being performed,but that is not an example of FIG. 5, where the time T4 ends before timeT5. To extend the example above, the group of three vibrations may berepeated every 7 to 10 sec.

Subsequent operations may depend on the determination of whether or notthe cardiac arrhythmia is so validated. According to another operation425 of FIG. 4, if it is determined that the cardiac arrhythmia is not sovalidated, execution may return to operation 410. Where it is written inthis document that it is determined that the cardiac arrhythmia is or isnot so validated, it means to be or not be validated according to thepreviously mentioned validation criterion, the determination of suchvalidation, etc.

When according to operation 425 it is determined that the cardiacarrhythmia is not so validated, execution may return to operation 410 byfurther optionally executing another operation 477. According tooperation 477, a closing HPI is caused to be output, in a manner and foran effect that are described later in this document for an operation 677of FIG. 6. In such a case, the discharge circuit can be controlled tonot deliver a shock for some time, e.g. at least 25 min from when theopening HPI was caused to be output at operation 472 of FIG. 4, becausethe patient may not need a shock for that time, or for that event.

In FIG. 5, box 525 can be another example of box 425. If it isdetermined that the cardiac arrhythmia is not so validated, timeline 541indicates that no warning HPI is caused to be output and timeline 597indicates that no shock is delivered. In addition, timeline 578indicates that a closing HPI event 577 may be caused to be output, suchas by operation 477.

Returning to FIG. 4, if at operation 425 it is determined that thecardiac arrhythmia is so validated then, according to another operation440, a warning HPI can be caused to be output. The warning HPI can beconfigured to communicate that a shock will be delivered imminently.

The warning HPI can be distinct from the opening HPI. In particular, theindications can be different in content, in the way they are delivered,and/or in the meaning that they are designed to convey to the patient.For example, in some embodiments the opening HPI communicates to thepatient that their WCD system has not made a determination yet, and itdoes not require the patient to do anything to avoid a shock. On theother hand, in many embodiments the warning HPI of operation 440 informsthat a shock is imminent unless the patient does something, like enter acancel input in the user interface.

According to an optional next operation 494, if a cancel input isreceived, execution may return to operation 410. In particular, the userinterface can be configured to receive a cancel input. Even if thecardiac arrhythmia is so validated, the discharge circuit can becontrolled to instead not deliver a shock responsive to the cardiacarrhythmia, if a cancel input is received by the user interface within atime window after the warning HPI of operation 440 is caused to beoutput.

Else, if at operation 494 a cancel input is not received then, accordingto another operation 499, the discharge circuit is instead controlled todeliver a shock, for example within 3 min from when the warning HPI wascaused to be output for that event, and preferably before 3 min passes.

In FIG. 5, from box 525, if it is determined that the cardiac arrhythmiais so validated, a timeline 542 indicates that a warning HPI event 543can take place, for example according to operation 440. In addition,timeline 598 indicates that a shock delivery event 599 may take place,while timeline 579 indicates that no closing HPI event takes place.

These embodiments that include an opening HPI can be combined with otherembodiments. For example, from this document alone, these otherembodiments include ones with a closing HPI, embodiments where there isconfirmation of the cardiac arrhythmia in addition to validation,embodiments with shocking if the patient has VF but not necessarily ifVT, a different delay or validation time for VT than for VF, a differentHPI for VT than for VF, etc.

In some embodiments, a WCD system may output a closing human-perceptibleindication (“HPI”), after detecting a shockable cardiac arrhythmia, andafter further determining that it will not shock. The closing HPI may beassociated with closing an event, such as when an event is closed insoftware, where a record is kept. Examples are now described.

FIG. 6 shows a flowchart 600 for describing methods according toembodiments. Flowchart 600 has many elements that are similar toflowchart 400 of FIG. 4. In addition, the sample series of events ofFIG. 5 may also result from methods of the flowchart of FIG. 6.

In FIG. 6, operations 610, 615, 620, 672, 625, 640 and 694 can beperformed as described respectively for operations 410, 415, 420, 472,425, 440, and 494 of FIG. 4. In other words, a shockable cardiacarrhythmia is detected, etc. Of those operations, at least operations672 and 694 are optional.

If, at operation 625 it is determined that the cardiac arrhythmia is sovalidated then, according to an operation 699, the discharge circuit canbe controlled to instead deliver a shock within some time from when itwas determined that the cardiac arrhythmia is so validated. The shockcan be delivered, for example within 2.5 min or less, for this event.

If, at operation 625 it is determined that the cardiac arrhythmia is notso validated, execution may return to operation 610 without shocking forthis event. In addition, according to another operation 677, a closingHPI is caused to be output. The closing HPI can be configured tocommunicate to the patient that it was decided not to shock responsiveto the cardiac arrhythmia, so the patient can relax and return to his orher other business. This may be communicated in a number of ways. Insome embodiments, the closing HPI includes a voice message, which cansay something like: “HAPPY THAT YOUR RHYTHM IS RESTORED, WILL NOT SHOCKTHIS TIME”. In alternate, and more discreet, embodiments the closing HPIincludes one or more vibrations. For example, a group of consecutivevibrations may be used, which have progressively diminishingintensities. If, at operation 625 it is determined that the cardiacarrhythmia is not so validated, the discharge circuit can be furthercontrolled to not deliver a shock for some time from when it wasdetermined that the cardiac arrhythmia is not so validated, for examplefor at least 25 min. Of course, this time can become shorter if thepatient has another event soon thereafter, and so on.

These embodiments that include a closing HPI can be combined with otherembodiments. For example, from this document alone, these otherembodiments include ones with an opening HPI, embodiments where there isconfirmation of the cardiac arrhythmia in addition to validation,embodiments with shocking if the patient has VF but not necessarily ifVT, a different delay or validation time for VT than for VF, a differentHPI for VT than for VF, etc.

In some embodiments, a WCD system may first determine whether or not thecardiac arrhythmia is validated, for example according to a validationcriterion. If so, the WCD system may further determine whether or notthe cardiac arrhythmia is confirmed according to a confirmationcriterion, and then shock or not shock accordingly. Examples are nowdescribed.

FIG. 7 shows a flowchart 700 for describing methods according toembodiments. In addition, FIG. 8 is a time diagram of a sample series ofevents that may result from methods of the flowchart of FIG. 7. Ofcourse, a different series of events may result from the methods of theflowchart of FIG. 7. The events of FIG. 8 are shown along a time axis812, with intercepts that are not to scale. This portion of thisdescription proceeds by referring to both diagrams.

In FIG. 7, operations 710, 715, 720, 725, 740, 794 and 777 can beperformed as previously described for respectively operations 410, 415,420, 425, 440, 494 and 677. In other words, a shockable cardiacarrhythmia is detected, etc. Of those operations, at least operations740, 794 and 777 are optional. In FIG. 8, timelines 810, 815, 820 can beas described for timelines 510, 515 and 520. In addition, an opening HPImay be caused to be output as per the above, but such is not shown so asnot to obscure the drawings.

If, at operation 725 it is determined that the detected cardiacarrhythmia is so validated then, according to another operation 770, acertain HPI can be caused to start being output. The certain HPI canaccomplish a number of functions. One such function may be to inform thepatient, who may be only tachycardic and thus conscious, that moreanalysis of their rhythm will be performed in the form of aconfirmation. Again, this may give the patient the confidence that he orshe will not be shocked unnecessarily, while they need not do anythingto prevent a shock. After starting being output, the certain HPI ofoperation 770 can continue, to sustain the patient's confidence. Forexample, in FIG. 8, timeline 870 shows the certain HPI, which startsbeing output at time T6, and lasts until time T8.

Returning to FIG. 7, after operation 770, according to another operation750 it can be further determined whether or not the cardiac arrhythmiais confirmed. In FIG. 8, the confirmation of operation 750 is shown by atimeline 850 as taking place between times T7 and T9. It will beappreciated that time T7 in this example is after time T6, which is whenthe certain HPI started being output.

The determination of operation 750 can be performed according to aconfirmation criterion, meaning depending on whether or not theconfirmation criterion is met. The confirmation criterion can bedifferent from or the same as the validation criterion. In someembodiments, the validation criterion can include that the cardiacarrhythmia is maintained for a validation time, the confirmationcriterion can include that the cardiac arrhythmia is maintained for aconfirmation time, and the confirmation time can be the same ordifferent from the validation time. In some embodiments, theconfirmation time is longer than the validation time, which is why thecertain HPI may help the patient with their comfort that their system isworking.

Subsequent operations may depend on the determination of whether thecardiac arrhythmia is so confirmed or not. Where it is written in thisdocument that it is determined that the cardiac arrhythmia is or is notso confirmed, it means to be or not be confirmed according to thepreviously mentioned confirmation criterion, the determination of suchconfirmation, etc.

According to another operation 755, if it is determined that the cardiacarrhythmia is not so confirmed, execution may return to operation 710,with optionally also executing operation 777 as mentioned above foroperation 677. In such a case, there may be no shocking for this eventin fact the discharge circuit can be controlled to not deliver a shockfor some time, e.g. at least 22 min from when the cardiac arrhythmia isnot so confirmed, because the patient may not need a shock for thattime. Of course, this time can become shorter if the patient has anotherevent soon thereafter, and so on.

If, at operation 755 it is determined that the cardiac arrhythmia is soconfirmed then shocking may be needed for this event. Thus, according toan operation 799, the discharge circuit can be controlled to deliver ashock within some time from when it was determined that the cardiacarrhythmia is so confirmed, for example within 4.8 min or preferablyless.

Similarly, referring to FIG. 8, from box 855, if it can be determinedwhether or not the cardiac arrhythmia is so confirmed. If not, thentimelines 841 and 897 can be as timelines 541 and 597, respectivelyindicating no warning HPI and no shock. Else, if the cardiac arrhythmiais so confirmed, then timeline 842 indicates a warning HPI event 843,and timeline 898 indicates a shock delivery event 899.

These embodiments that include confirmation in addition to validationcan be combined with other embodiments. For example, from this documentalone, these other embodiments include ones with shocking if the patienthas VF but not necessarily if VT, a different delay or validation timefor VT than for VF, a different HPI for VT than for VF, etc.

In some embodiments, a WCD system may detect whether a cardiacarrhythmia is of a first type or of a second type. If the cardiacarrhythmia is of the first type, the WCD system may shock the patientanyway. If the cardiac arrhythmia is of the second type, however, theWCD system may determine whether or not the cardiac arrhythmia isconfirmed, for example according to a confirmation criterion, and thenshock or not shock accordingly. Examples are now described.

FIG. 9 shows a flowchart 900 for describing methods according toembodiments. In FIG. 9, operations 910 and 915 can be performed asdescribed above for operations 410 and 415 respectively. In other words,a shockable cardiac arrhythmia is detected, etc. In addition, an openingHPI can optionally be caused to be output, for example prior tocompleting the determination of the type at operation 930 that isdescribed later. Moreover, it may be optionally determined whether ornot the cardiac arrhythmia is validated according to a validationcriterion. In such embodiments, the opening HPI can be caused to beoutput prior to completing the determination of whether the cardiacarrhythmia is so validated. Subsequent actions, such as determining thetype, validating, etc. may be performed responsive to determining thatthe cardiac arrhythmia is so validated.

If at operation 915 a cardiac arrhythmia is detected then, according toanother operation 930, it may be determined whether a type of thecardiac arrhythmia is at least one of a first type (“CA1”) and a secondtype (“CA2”). There can be two, three, or more possible such types.Embodiments may act differently, depending on the type determined atoperation 930.

In some embodiments, the first type (“CA1”) of detected cardiacarrhythmias includes Ventricular Fibrillation. In some embodiments, CA1includes Ventricular Tachycardia, where a heart rate of the patient hasa value larger than a first heart rate threshold. An example is nowdescribed.

FIG. 10 shows a diagram 1030, where detected cardiac arrhythmias may beplotted according to their heart rate. In diagram 1030 a HEART RATE axishas a first heart rate threshold HRT1. Suggested values for HRT1 arediscussed below. The type of cardiac arrhythmias whose heart rate has avalue larger than HRT1 can be determined to be CA1. The remainingcardiac arrhythmias can be determined to be either all of the same type(e.g. CA2), or further subdivided according to additional types, etc. Itwill be appreciated, then, that fast VT may be thus classified as typeCA1, while slower VT otherwise.

In some embodiments, the second type (“CA2”) of detected cardiacarrhythmias includes Ventricular Tachycardia, where a heart rate of thepatient has a value less than a second heart rate threshold. An exampleis now described.

FIG. 11 shows a diagram 1130, where detected cardiac arrhythmias may beplotted according to their heart rate. In diagram 1130 a HEART RATE axishas a second heart rate threshold HRT2. Suggested values for HRT1 arediscussed below. The type of cardiac arrhythmias whose heart rate has avalue less than HRT2 can be determined to be CA2. The remaining cardiacarrhythmias can be determined to be either all of the same type (e.g.CA1), or further subdivided according to additional types, etc. It willbe appreciated, then, that slower VT may be thus classified as type CA2.

In some embodiments, if a value of the heart rate of the patient iswithin a range, the type is determined to be CA1 or CA2 depending bothon the value of the heart rate and on a value of a width of detected QRScomplexes of the patient. An example is now described.

FIG. 12 shows a diagram 1230, where detected cardiac arrhythmias may beplotted according to both their heart rate and the width of QRScomplexes, based on orthogonal axes. The horizontal axis is for theheart rate. The vertical axis is for the QRS width, which can bemeasured by the algorithm at the base of the QRS complex. It will benoted that the vertical axis starts at a minimum threshold value WTHR.Above that value, QRS complexes start deteriorating. Below that value,it is possible that no shock is advised. A good value for WTHR can beabout 80 msec.

In diagram 1230 a broken line 1231 divides the space in two sectors orzones, one for CA1 and one for CA2. At least the type of cardiacarrhythmias whose heart rate has a value larger than HRT3 can bedetermined to be CA1, and at least the type of cardiac arrhythmias whoseheart rate has a value less than HRT4 can be determined to be CA2. Inaddition, if the value of the heart rate is within the range of HRT4 andHRT3, then the type can be determined depending both on the value of theheart rate on the horizontal axis and on a value of a width of detectedQRS complexes on the vertical axis. The determination takes place fromline segment 1232 of broken line 1231.

A good value for HRT4 is 170 bpm (beats per minute). A good value forHRT3 is 200 bpm. A good value for W3 is 120 msec, and for W4 is 150msec. Once values for these parameters are determined, then an equationcan be constructed for line segment 1232 using analytic geometry, for aprocessor to use.

In the example of FIG. 12, broken line 1231 has only linear segments,but that is only an example. Linear segments are preferred, because thecomputation for the determination of operation 930 is easier, as seenfor line segment 1232.

Where performing such computations based on the QRS width would be tootaxing on resources, and where only two types need be determined, thenFIGS. 10 and 11 may be used in a combined form. In such a case, HRT1 canbe set equal to HRT2, and both can have a value between the proposedvalues of HRT3 and HRT4, such as 200 bpm. In other words, the heartrhythms can be separated according to a certain heart rate threshold:CA1 may include a rhythm where a heart rate of the patient has a valueless than the certain heart rate threshold, while CA2 may include arhythm where the heart rate has a value larger than the certain heartrate threshold. The certain heart rate threshold can be, for example 200bpm; a rate higher than that can be designated as the VF zone, while arate of 170-200 bpm can be designated as the VT zone.

In some embodiments, there are two types of cardiac arrhythmias:shockable VF/shockable VT. In addition to the heart rate and the QRSwidth, one may further incorporate another attribute called QRSorganization. QRS organization might be assessed by cross-correlatingdetected QRS complexes. Rhythms in which the QRS complexes show a highcorrelation would be said to be relatively “organized,” while rhythmswith a low correlation would be “disorganized.”

Accordingly, there may be no shock while the heart rate is <150 bpm andthe QRS width <120 msec. At least monomorphic VT may be identified as aheart rate >150 bpm, QRS width >120 msec, and high QRS organization. VFmay be identified as a heart rate is >200 bpm, QRS width >120 msec, andlow QRS organization.

In some embodiments where the physiological signal is an ECG waveform,the distinction between CA1 and CA2 is based on an amplitude of an ECGwaveform. A type of a cardiac arrhythmia can be CA1 if its ECG waveformhas an amplitude smaller than a threshold amplitude, and CA2 if its ECGwaveform has an amplitude larger than the threshold amplitude. Thethreshold amplitude can be a suitable value, for example 200 μV.

Returning to FIG. 9, according to another operation 931, it is inquiredwhich was the type of the detected cardiac arrhythmia determined atoperation 930. In the examples of this document, cardiac arrhythmiaswhose type is CA1 are deemed more severe than otherwise, e.g. thosewhose type is CA2. Operation 931 anticipates that there could be two oreven more types. For example, another type can be Atrial Fibrillation(“AF”).

In some embodiments, if at operation 931 it is determined that the typeis CA1 then, according to an operation 999, the discharge circuit can becontrolled to deliver a shock within sometime of determining the type,for example within 2.9 min and preferably less than that.

In some embodiments, if at operation 931 it is determined that the typeis CA2 then, according to another operation 951, it can be furtherdetermined whether or not the cardiac arrhythmia is confirmed. Thisconfirmation can be performed in a number of ways, as will be seen laterin this document.

According to one more operation 956, if the cardiac arrhythmia is soconfirmed at operation 951, then the discharge circuit can be controlledto deliver a shock according to operation 999. Operation 999 may be thusperformed within some time from when the cardiac arrhythmia is soconfirmed at operation 951, for example within 4.8 min. But if thecardiac arrhythmia is not so confirmed at operation 951, then executionmay return to operation 910, and the discharge circuit can be controlledto not deliver a shock for some time. This time can be, for example atleast 24 min from when the cardiac arrhythmia is not so confirmed atoperation 951. In addition, a closing HPI may be caused to be outputresponsive to the cardiac arrhythmia not being so confirmed, inconjunction with returning to operation 910.

Operation 951 may be performed in a number of ways. It should be kept inmind that, in many embodiments, the detected cardiac arrhythmia at thistime is known to be of the second type, which will hopefullyself-terminate without needing to administer a shock. Examples are nowdescribed.

In some embodiments, it is determined whether or not the cardiacarrhythmia is confirmed according to a confirmation criterion. In someembodiments, the confirmation criterion includes that the cardiacarrhythmia is maintained for a confirmation time. In some embodiments,the confirmation criterion includes that a heart rate of the patientincreases during a confirmation time. Additional embodiments are nowdescribed.

FIG. 13 shows a flowchart 1351 for describing methods according toembodiments. Some of these methods may be applied to flowchart 900, orothers where a detected cardiac arrhythmia is being confirmed.

According to an operation 1353, a confirmation timer may be started.According to another operation 1310, a patient physiological signal maybe monitored. At this point, if flowchart 1351 is applied to flowchart900, the patient physiological signal may help detect a cardiacarrhythmia of the second type (“CA2”).

According to another operation 1314, it is inquired what cardiac rhythmis being detected. If the rhythm is a normal sinus rhythm (NSR), it maybe that the heart rhythm has been restored by itself. Then, according toa state 1356, the cardiac arrhythmia is not confirmed. If flowchart 1351is being applied to flowchart 900, execution then returns to operation910.

If at operation 1314 of FIG. 13 the cardiac arrhythmia is of the firsttype (“CA1”), such as VF or fast VT, execution may proceed to operation1399. The latter may be performed as operation 999 in flowchart 900.

If at operation 1314 of FIG. 13 the cardiac arrhythmia is still of thesecond type (“CA2”), it may be that the patient has been experiencingVT. The above described option of checking as to whether the heart ratehas been increasing persistently may be checked at this time.

At this stage, the patient may have become very uncomfortable with theircardiac rhythm, in fact so uncomfortable that the patient may prefer tobe shocked over waiting for the arrhythmia to self-terminate. In someembodiments of a WCD system, the user interface is further configured toreceive a shock input by the patient, such as by the patient pushing abutton titled: “SHOCK ME NOW”. According to another operation 1357, ifsuch a shock input is received, execution may proceed to operation 1399.In other words, in such embodiments, if the type has been determined tobe CA2, the discharge circuit can be controlled to deliver a shockresponsive to the received shock input. Operation 1399 can be performedwithin sometime after receiving the shock input, for example within 1.6min of receiving the shock input.

If at operation 1357 no shock input has been received, then according toanother operation 1358 it is inquired whether the confirmation timerthat started at operation 1353 has timed out. If not, execution mayreturn to operation 1310. If yes then, according to a state 1359, thecardiac arrhythmia is confirmed, and execution may proceed to operation1399.

These embodiments that shock a patient with VF but not necessarily withVT can be combined with other embodiments. For example, from thisdocument alone, these other embodiments include ones with a differentdelay or validation time for VT than for VF, a different HPI for VT thanfor VF, etc.

In some embodiments, a WCD system may detect whether a cardiacarrhythmia is of a first type or of a second type. The WCD system mayvalidate the detected cardiac arrhythmia, and output an HPI with adifferent delay, depending on the type. Examples are now described.

FIG. 14 shows a flowchart 1400 for describing methods according toembodiments. In addition, FIG. 15 is a time diagram of a sample seriesof events that may result from methods of the flowchart of FIG. 14. Ofcourse, a different series of events may result from the methods of theflowchart of FIG. 14. The events of FIG. 15 are shown along a time axis1512, with intercepts that are not to scale. This portion of thisdescription proceeds by referring to both diagrams.

In FIG. 14, operations 1410, 1415, 1430 and 1431 can be performed asdescribed above for respective operations 410, 415, 930 and 931. Inother words, a shockable cardiac arrhythmia is detected, its type isdetermined, etc.

In parallel referring to FIG. 15, timelines 1510 and 1515 can be asdescribed for timelines 510 and 515. Moreover, timeline 1530 shows atype determination event 1531 of performing operation 1430, which startsat time T11 and ends at time T12.

In addition, although not shown in flowchart 1400 or in FIG. 15, in someembodiments an opening HPI is caused to be output responsive todetecting the cardiac arrhythmia, prior to completing the determinationof the type. Moreover, the cardiac arrhythmia may be validated accordingto a validation criterion, and the opening HPI can be caused to beoutput prior to completing the determination of whether the cardiacarrhythmia is so validated. In some embodiments, type determinationevent 1531 is performed quickly and easily during such a validation, andthus it does not delay other actions.

If at operation 1431 it is determined that the type is CA1 then,according to another operation 1432, a first warning HPI is caused to beoutput. Operation 1432 may be performed after a first delay periodelapses, since the type is determined at operation 1430.

If at operation 1431 it is determined that the type is CA2 then,according to another operation 1436, a second warning HPI is caused tobe output. The first warning HPI can be the same or different than thesecond warning HPI. It is preferred that they are the same, for thepatient to not have to be trained to many different commands.

Operation 1436 may be performed after a second delay period elapses,since the type is determined at operation 1430. The second delay periodmay have a duration at least 20% different from a duration of the firstdelay period. For example, the first delay period could be up to 10 sec,or even 20 sec. On the other hand, the second delay period can have aduration of 5-60 sec, and even longer, both for better analysis and alsoin order to give a VT the opportunity to self-terminate. In embodiments,these delay periods are programmable.

After operation 1432 or 1436, according to an operation 1499, thedischarge circuit can be controlled to deliver a shock responsive to thecardiac arrhythmia. In some embodiments, this shock is canceled if,according to an operation 1494, a cancel input is received within a timewindow. In other words, the discharge circuit can be controlled toinstead not deliver a shock responsive to the cardiac arrhythmia andbypass operation 1499, if a cancel input is received by the userinterface within a time window after the first warning HPI or the secondwarning HPI is caused to be output.

In FIG. 15, box 1531 replicates the decision of box 1431. In someembodiments, if the type is CA1, it may be determined during the firstdelay period whether the cardiac arrhythmia is confirmed according to aCA1 confirmation criterion. The CA1 confirmation criterion could be thatthe cardiac arrhythmia is maintained for a CA1 confirmation time.Timeline 1551 shows the confirmation, where the CA1 confirmation timelasts between T12 and T14. The CA1 confirmation time may be, for example10 sec if CA1 includes VF. Timeline 1532 then shows the first warningHPI event 1537 that starts at a later time T15.

In such embodiments, if the type is CA2, it may be determined during thesecond delay period whether the cardiac arrhythmia is confirmedaccording to a CA2 confirmation criterion. The CA2 confirmationcriterion could be that the cardiac arrhythmia is maintained for a CA2confirmation time. Timeline 1556 shows this confirmation, where the CA2confirmation time lasts between T12 and T16. Timeline 1536 then showsthe second warning HPI event 1533 that starts at a later time T17. Inthis example, the CA2 confirmation time has a duration at least 20%different from a duration of the CA1 confirmation time. The CA2confirmation time may be, for example 45 sec if CA2 includes VT. Thedifferences in the confirmation times may account for the differences inthe respective delay periods.

FIG. 15 does not show the shock event that may follow the warning HPIs.This was done only not to clutter FIG. 15.

These embodiments that have a different delay or validation time for VTthan for VF can be combined with other embodiments. For example, fromthis document alone, these other embodiments include ones with adifferent HPI for VT than for VF, etc.

In some embodiments, a WCD system may detect whether a cardiacarrhythmia is of a first type or of a second type. The WCD system mayoutput different HPIs for the first type than the second type. Examplesare now described.

FIG. 16 shows a flowchart 1600 for describing methods according toembodiments. In FIG. 16, operations 1610, 1615, 1630, 1631, 1694 and1699 can be performed as described above for respective operations 1410,1415, 1430, 1431, 1494 and 1499. In other words, a shockable cardiacarrhythmia is detected, its type is determined, etc.

In addition, although not shown in flowchart 1600, in some embodimentsan opening HPI is caused to be output responsive to detecting thecardiac arrhythmia, prior to completing the determination of the type.Moreover, the cardiac arrhythmia may be validated according to avalidation criterion, and the opening HPI can be caused to be outputprior to completing the determination of whether the cardiac arrhythmiais so validated.

If at operation 1631 it is determined that the type is CA1 then,according to another operation 1682, a first HPI is caused to be output.Else, if the type is CA2, according to another operation 1686 a secondHPI is caused to be output.

The first HPI can be different from the second HPI for a number ofreasons. For instance, the first HPI can be a warning HPI as describedabove, in which case entering a cancel input will avert a shock. On theother hand, the second HPI can be an HPI where the patient is informedthat their rhythm is still being analyzed, whether that means beingvalidated or confirmed.

The first HPI can be different from the second HPI in a number of ways.Examples are now described.

In some embodiments, the user interface includes at least a first and asecond output device. The HPIs can come from different devices, in otherwords the first HPI can be output by the first output device, while thesecond HPI can be output by the second output device.

In some embodiments, the first and the second HPI can be from the samedevice. Examples are now described.

In some embodiments, the user interface includes a screen, but thedisplayed images are different. In other words, the first HPI can be afirst image displayed by the screen, while the second HPI can be asecond image displayed by the screen, which is different than the firstimage.

In some embodiments, the user interface includes a speaker that can playone or more audible sounds, but the sound messages are different. Inother words, the first HPI can be a first sound message output by thespeaker, while the second HPI can be a second sound message output bythe speaker, which is different from the first sound message.

In some embodiments, the user interface includes an output device thatcan cause an HPI to be output at different intensity levels, be thatlouder for sound, brighter for light, more intense for vibration, and soon. The first HPI can be output by the output device at a firstintensity level, while the second HPI can be output by the output deviceat a second intensity level, which is at least 20% different than thefirst intensity level. The intensity level may be measured by energy toactuate the device, perceived intensity by the user, etc.

In some embodiments, a WCD system may detect a shockable cardiacarrhythmia of the patient. The WCD system may try to validate or confirmthe arrhythmia. It may fail to validate it in instances where, forexample, the arrhythmia self-terminates relatively quickly. In suchembodiments the WCD system, which has one or more output devices, mightnot output any loud sound before validation is completed, so as not toembarrass the patient to bystanders nearby. In addition, the patient maybe spared of having to press the buttons to prove they are alive, and soon. In some of these embodiments, the WCD system might even not outputany sound at all before validation is completed.

In some embodiments, the WCD system may try to validate or confirm thearrhythmia for a longer time than in the prior art, so as to give it afurther chance to self-terminate. In such embodiments, the WCD systemmay transmit or even record data of the self-terminating arrhythmia forlater analysis. In some of these embodiments, the WCD system may notifythe patient only discreetly, or even not at all. Examples are nowdescribed.

FIG. 17 shows a flowchart 1700 for describing methods according toembodiments where a detected cardiac arrhythmia is given a furtherchance to self-terminate, sometimes by being validated for a longertime. In addition, FIG. 18 is a time diagram of a sample series ofevents that may result from methods of the flowchart of FIG. 17. Ofcourse, from the methods of the flowchart of FIG. 17, a series of eventsmay result that is different than the sample series of events of FIG.18. The events of FIG. 18 are shown along a time axis 1812, with timeintercepts that are not to scale. This portion of this descriptionproceeds by referring to both FIGS. 17 & 18.

It will be understood that flowchart 1700 can be performed for allpossible cardiac arrhythmias, or only certain types of ones. Inaddition, flowchart 1700 can be performed for all possible shockablecardiac arrhythmias, or only certain types of ones For example,flowchart 1700 may be performed only for VT but not for VF, the reverse,and so on.

In FIG. 17, operation 1710 can be performed as described previously foroperations 410, 610, 710, etc. In FIG. 18, a timeline 1810 indicatesthat the physiological input starts being received at a time T1, byswitching from a low value to a high value at that time.

Moreover, a measurement circuit such as measurement circuit 220 can beconfigured to render physiological inputs from the physiological signalof the patient monitored at operation 1710 of FIG. 17. The physiologicalsignal may be an ElectroCardioGram (ECG) signal, and the physiologicalinputs may be sections of an ECG waveform, taken at different times.

In FIG. 17, an operation 1715 can be performed as described previouslyfor operations 415, 615, 715, etc. While at operation 1715 no cardiacarrhythmia is being detected, execution can return to operation 1710.This detection or not of a cardiac arrhythmia is shown in FIG. 18 alonga timeline 1815. There is no detection while timeline 1815 has a lowvalue. Detection may happen at time T2, at which time timeline 1815changes to a high value. At that time, detection may have been performedusing inputs received earlier.

It should be remembered that FIGS. 17 & 18 are from the point of view ofthe WCD system, its processor, and so on. Accordingly, while a cardiacarrhythmia may be detected at time T2, the onset or first time point ofthe cardiac arrhythmia may be a little earlier than that, and detectionat time T2 may be somewhat delayed from that onset or first time point.

Returning to FIG. 17, if detection happens at operation 1715 then,according to another operation 1721, it can be determined whether or notthe detected cardiac arrhythmia meets a validation criterion. Thedetermination can be performed by a validation process that lasts 5-60sec, or even longer. For example, the validation criterion may includethat the detected cardiac arrhythmia needs to be maintained for theabove mentioned threshold validation time of 5-60 sec, or even longer.In FIG. 18, this prolonged validation time lasts until time T25.

In some embodiments, the validation time is 25 sec, or even 35 sec,which is prolonged over the prior art of FIG. 3C. This prolongedvalidation time can give a chance to the cardiac arrhythmia toself-terminate. In some embodiments, the type of the cardiac arrhythmiais also detected, and the validation lasts for such a prolonged timeonly for certain types of cardiac arrhythmias, e.g. for a ventriculartachycardia, but not for ventricular fibrillation. The prolongedvalidation period may therefore result in fewer instances when loudsounds such as alarms are output, and so on.

In embodiments, according to another operation 1772, one of speakers271, 272 that is capable of outputting a loud sound is caused to outputno sound louder than 58 decibel (db) as measured at a distance of, say,2′ (i.e. 2 feet) from the speaker. This operation 1772 may be performedwhile operation 1721 is being performed, i.e. while the determination isbeing performed of whether or not the detected cardiac arrhythmia meetsthe validation criterion. In fact, no sound at all may be output whileoperation 1721 is being performed, when in fact this speaker may becapable of outputting a louder sound, as will be seen later in thisdescription.

Subsequent operations may depend on the determination of operation 1721,i.e. on whether or not the cardiac arrhythmia meets the validationcriterion. According to another operation 1725 of FIG. 17, if it isdetermined that the cardiac arrhythmia does not meet the validationcriterion then the discharge circuit can be controlled to not cause ashock to be delivered responsive to the cardiac arrhythmia detected atoperation 1715.

Execution may then return to operation 1710. It will be appreciatedthat, in some such instances where the detected cardiac arrhythmia doesnot meet the validation criterion, the speaker can be caused to outputno sound at all, or no sound louder than 58 db, for another at least 10minutes (min) after the determination has been performed. Thisadditional time, when considered together with the time of operation1772 can amount to a long quiet time for a cardiac arrhythmia thateventually self-terminated.

In parallel, in FIG. 18, operation 1825 reflects operation 1725. If atoperation 1825 it is determined that the cardiac arrhythmia does notmeet the validation criterion, then a timeline 1841 for a loud soundshows no loud sound for a quiet time period that lasts from T1 until atleast time T26. This quiet time period can be the above-described 10min. And, a timeline 1897 for a shock shows no shock for the same timeperiod.

On the other hand, if at operation 1725 of FIG. 17 it is determined thatthe cardiac arrhythmia meets the validation criterion then, according toan operation 1740, the speaker of operation 1772 may be caused to outputa loud sound, for example a sound louder than 60 db, as measured at adistance of 2′ from the speaker. In this case, the speaker may be asiren, and be even louder than 60 db, such as over 100 db, given thatthe patient may be shocked and that no one should be touching them.Then, according to another operation 1799, the discharge circuit can befurther controlled so as to cause a shock to be delivered. Of course,additional operations may be performed, such as intervening warnings, anopportunity to cancel the shock, etc.

In parallel, in FIG. 18, if at operation 1825 it is determined that thecardiac arrhythmia meets the validation criterion, then an alternatetimeline 1842 for a loud sound shows a loud sound 1843, so as to alertbystanders. In addition, a timeline 1898 for a shock shows a shock 1899.

Moreover, as seen above, some embodiments include another speaker,namely the other of 271, 272 whose sound can be controlled as describedin the above few paragraphs for the first speaker. In particular, theother speaker may be caused to output no sound louder than 58 db asmeasured at a distance of 2′ from the other speaker, or no sound at all,while the determination being performed of whether or not the detectedcardiac arrhythmia meets the validation criterion.

In the above, the prolonged time period of validating the detectedcardiac arrhythmia can be thought of as being part of a quiet timeperiod. Indeed, while the WCD system may include a potentially loudsiren, that siren can be kept from outputting a loud sound. Moreover,the prolonged time period of validating the detected cardiac arrhythmiacan be further thought of as being part of a serene time period, becauseno defibrillation shock is being delivered. Each of the quiet timeperiod and the serene time period can be considered to start at anysuitable starting point, such as from when the cardiac arrhythmia wasfirst detected, or when a determination started as to whether or not avalidation criterion is met. And, if the arrhythmia self-terminates, thequiet time period and the serene time period can be extended for longer,e.g. 10 min or longer, as already mentioned above.

Additional measures can be taken for the patient's privacy and dignity.Just like with loud sounds, bright lights can be lit when an arrhythmiais detected and validated. Such lights can be lit only discreetly, ornot lit up at all, however, if the arrhythmia is not so validated.

In some embodiments, the data about the quickly self-terminatingarrhythmia may be transmitted by communication module 290 to a remotecare giver for analysis, without outputting a loud sound. This may beperformed with or without the prolonged validation period that wasdescribed with reference to FIG. 17. Examples are now described.

FIG. 19 shows a flowchart 1900 for describing methods according toembodiments where data from self-terminating cardiac arrhythmias istransmitted by a WCD system without sounding loudly due to these cardiacarrhythmias. As with FIG. 17, flowchart 1900 can be performed for allpossible cardiac arrhythmias, or only certain types of ones.

Flowchart 1900 has many elements that are similar to flowchart 1700 ofFIG. 17. Operations 1910 and 1915 may be performed similarly tooperations 1710, 1715, respectively.

If detection happens at operation 1915 then, according to anotheroperation 1922, it can be determined whether or not the detected cardiacarrhythmia meets a validation criterion. The determination can beperformed by a validation process that can last for any suitableduration. Operation 1972 may be performed similarly with operation 1772.

Subsequent operations may depend on the determination of operation 1922,i.e. on whether or not the cardiac arrhythmia meets the validationcriterion. According to another operation 1925 of FIG. 19, if it isdetermined that the cardiac arrhythmia does not meet the validationcriterion then, according to an operation 1976, communication module 290can be caused to transmit data about the detected cardiac arrhythmia.This transmission may happen at any suitable time. In embodiments, thecommunication module is caused to transmit the data within 10 min ofdetermining that the detected cardiac arrhythmia does not meet thevalidation criterion, or an even shorter time. This may give a remotecare-giver the opportunity to call the patient, etc.

Furthermore, if it is determined that the detected cardiac arrhythmiadoes not meet the validation criterion, the discharge circuit can becontrolled to not cause a shock to be delivered responsive to thecardiac arrhythmia detected at operation 1915. Then execution may returnto operation 1910. It will be appreciated that, in some such instanceswhere the detected cardiac arrhythmia does not meet the validationcriterion, the speaker can be caused to output no sound at all, or nosound louder than 58 db, for another at least 10 min after thedetermination has been performed. This additional time, when consideredtogether with the time of operation 1972 can amount to a long quiet timefor a cardiac arrhythmia that eventually self-terminated.

On the other hand, if at operation 1925 of FIG. 19 it is determined thatthe cardiac arrhythmia meets the validation criterion, then operations1940, 1999 can be performed as was described for operations 1740, 1799,respectively.

Additional variations are possible, similarly with the embodiment ofFIG. 17. For example, any additional speaker(s) of the WCD system can becaused to output no sound louder than 58 db as measured at a distance of2′ from the speaker, or no sound at all, while the determination ofoperation 1922 being performed. And, similarly with lights, which can belit brightly for a validated arrhythmia, and discreetly or not at allfor a non-validated arrhythmia. Moreover, operation 1976 may take placeat one or more different and/or additional places in flowchart 1900, forexample after the YES decision of operations 1915 or 1925, afteroperations 1940 or 1999, etc.

Moreover, memory 238 of FIG. 2 can be configured to store data about thedetected cardiac arrhythmia. In operations, data about the detectedcardiac arrhythmia can be caused to be stored in memory 238, etc.

In some embodiments, the data about the quickly self-terminatingarrhythmia may be stored in memory 238 for later analysis, withoutoutputting a loud sound. This may be performed with or without theprolonged validation period that was described with reference to FIG.17, and with or without the transmission that was described withreference to FIG. 19. Examples are now described.

FIG. 20 shows a flowchart 2000 for describing methods according toembodiments where data of some self-terminating cardiac arrhythmias islong-term stored by a WCD system, without sounding loudly due to thesecardiac arrhythmias. As with FIGS. 17 and 19, flowchart 2000 can beperformed for all possible cardiac arrhythmias, or only certain types ofones.

The operations of flowchart 2000 are now described for themselves, andalso in conjunction with an operating example. In addition, FIG. 21 is atime diagram of a sample series of events that may result from methodsof the flowchart of FIG. 20 and from the operating example. Of course,from the methods of the flowchart of FIG. 20, a series of events mayresult that is different than the sample series of events of FIG. 21.The events of FIG. 21 are shown along a time axis 2112, with interceptsthat are not to scale. This portion of this description proceeds byreferring to both FIGS. 20 & 21.

In FIG. 20, operation 2010 can be performed as described previously foroperations 410, 610, 710, etc. In FIG. 21, a timeline 2110 indicatesthat the physiological input starts being received at a time T1, byswitching from a low value to a high value.

Moreover, a measurement circuit such as measurement circuit 220 can beconfigured to render physiological inputs from the physiological signalof the patient monitored at operation 2010 of FIG. 20. The physiologicalsignal may be an ECG signal, and the physiological inputs may besections of an ECG waveform, taken at different times.

In an operating example that starts being described now in parallel withflowchart 2000, a first, then a second, then a third, and then a fourthphysiological input become available due to operation 2010. Accordingly,values V1, V2, V3, V4 can be derived from the first, second, third, andfourth physiological inputs, respectively. In FIG. 21, a values timeline2111 indicates the times when these values V1, V2, V3, V4 are derived.Indeed, value V1 is derived between T1 and T2, value V2 between T2 andT18, value V3 between T18 and T19, and value V4 after T19.

According to a next operation 2016 of FIG. 20, next data can be storedin a memory of the WCD system, such as memory 238 of FIG. 2. The term“next data” is general, and may apply to different data that is beingmade available, as this operation 2016 is repeated a number of times bybeing in a loop. The storing of operation 2016 can be over-writeable orlonger term as may have been determined from a previous operation, andas will be seen later in this document.

In the operating example for FIG. 20, during the first time thatoperation 2016 is performed, the next data that is stored in the memorycan be first values V1 that are derived from the first physiologicalinput made available due to operation 2010. If the first physiologicalinput is a section of an ECG waveform, then these first values V1 can betime values of a section of the ECG waveform, or values representativeof salient features of the ECG waveform section, and so on.

According to a next operation 2017 of FIG. 20, it is inquired whether acardiac arrhythmia of the patient is detected from the last-stored data.The last-stored data can be the data that was stored in the memoryaccording to the latest storing operation, i.e. the last time thatoperation 2016 was executed. It will be understood that this can meanany cardiac arrhythmia, or only certain types of arrhythmias that are ofpotential interest, whether shockable or not. Actually, the type of thiscardiac arrhythmia can be detected from the physiological input, eitheritself or from the data, values, etc. that are derived from thephysiological input.

At operation 2017, the answer can be yes or no. As seen briefly fromtimeline 2115 of FIG. 21, in the operating example of this descriptionthe answer will be yes for values V2, and no for values V1, V3, V4. Inother words, the cardiac arrhythmia of this example first manifestedwhen values V2 were derived, but self-terminated by the time values V3were derived.

If, at operation 2017, the answer is no, then at a subsequent operation2018, the storing of the last-stored data is or becomes over-writable inthe memory, so as to liberate memory space and conserve on requirementsof memory. This operation 2018 may or may not be an explicit operation.For example, operation 2018 may be implemented implicitly by havingoperation 2016 be performed by writing to a memory, or portion of amemory, and then writing in the same memory over the data after sometime, for example after two minutes.

In the operating example for FIG. 20, operation 2018 is performed thefirst time for stored values V1. The stored values V1 are indicated inFIG. 20 by an associated square V1; the fact that the storing of thesevalues V1 is now over-writable is indicated by showing square V1 withdotted lines.

After operation 2018, execution may return to operation 2010, forultimately receiving the next data that will be stored per operation2016. This closes the loop of operations 2010, 2016, 2017, 2018, for aslong as no arrhythmia is being detected.

In FIG. 21, the detection of a cardiac arrhythmia is shown along atimeline 2115. For as long as there is no detection, i.e. between timesT1 and T2, timeline 2115 has a low value.

In the operating example for FIG. 20, during the second time thatoperation 2016 is performed, the next data that is stored in the memorycan be second values V2 that are derived from the second physiologicalinput made available due to operation 2010. Moreover, as these secondvalues V2 become stored in the memory, at least some of the stored firstvalues V1 can become over-written by the storing of the second valuesV2. This over-writing can be permitted due to having performed operation2018 earlier.

In this operating example, when operation 2017 is then repeated forthese second values V2, the answer is yes: a cardiac arrhythmia of thepatient is indeed detected. Actually, the cardiac arrhythmia can bedetected from the second physiological input, either itself or from thesecond values that are derived from the second physiological input.These second values could be stored as per operation 2016 or not. InFIG. 21, the onset of the detection is shown at time T2, at which timetimeline 2115 changes to a high value.

At operation 2017 of FIG. 20, since the answer is yes then, according toa subsequent operation 2019, the storing of the last-stored data is orbecomes longer-term in the memory. Here the notion of “longer-term” isintended to distinguish from the over-writeable aspect of operation2018. At least some of the data with such longer-term storing will notbe overwritten, and will thus be available for later review. Of course,they may become over-writable after the review, and so on.

This operation 2019 may or may not be an explicit operation. Forexample, operation 2019 may be implemented implicitly by havingoperation 2016 be performed using a memory that is not being re-writtenon, after some time. Or, operation 2019 may be performed explicitly bycopying the relevant data to a different portion of the memory, as willbe seen, for example, in FIG. 23.

In FIG. 21, the longer-term storing is shown by a timeline 2119. In thisexample, and for this depiction, the longer-term storing is shown ascoextensive with the detected arrhythmia of timeline 2115, to betterindicate the preference that what is stored is the data of thearrhythmia only. In embodiments, however, there can be a time delay fromwhen the arrhythmia is first detected until the storing of thearrhythmia's data becomes longer-term. Plus, data that follows aself-terminating arrhythmia can give additional insights to reviewers,which is why it might be desirable to store also such data.

In the operating example for FIG. 20, operation 2019 is thus performedfor stored values V2, because that is the last-stored data. The storedvalues V2 are indicated in FIG. 20 by an associated square V2; the factthat the storing of these values V2 is now longer-term is indicated byshowing square V2 with solid lines.

In FIG. 20, according to a subsequent operation 2066, next data isstored. Operation 2066 can be performed similarly to operation 2016. Thedifference is that operation 2066 is performed after a cardiacarrhythmia has been detected at operation 2017.

In the operating example for FIG. 20, the first time that operation 2066is performed, the next data that becomes stored in the memory can bethird values V3 that are derived from the third physiological input madeavailable due to operation 2010. Moreover, as these third values V3become stored in the memory, at least some of the stored second valuesV2 do not become over-written by the storing of the third values V3. Infact, in some embodiments, none of the stored second values V2 becomeover-written by the storing of the third values V3. Such over-writing isprevented due to operation 2019 having been performed, which isresponsive to the cardiac arrhythmia having been detected at operation2017.

In FIG. 20, according to a subsequent operation 2025, it can bedetermined whether or not the cardiac arrhythmia detected at operation2017 is validated. This validation operation 2025 may be implemented bydetermining whether or not the detected cardiac arrhythmia meets avalidation criterion. There can be a number of such criteria forvalidation. In some embodiments, the validation criterion includes adetermination of whether or not a cardiac arrhythmia is detected alsofrom the subsequent third physiological input, or from at least some ofthe third values V3. It should be noted that the type of this cardiacarrhythmia sought to be detected for validation operation 2025 could bethe same or different type than the cardiac arrhythmia detected atoperation 2017. In some embodiments, the determination of whether or notthe detected cardiac arrhythmia meets the validation criterion isperformed by a validation process that lasts for at least 25 sec orlonger.

If at operation 2025 the answer is yes, then subsequent operations 2040,2099 may be implemented similarly to operations 1740, 1799, forsounding, then shocking, etc.

In FIG. 21, validation operation 2125 could result in differenttimelines 2198 (eventual shock), or 2197 (no shock for some time andfrom these inputs, since this arrhythmia was not validated). In thisexample, there is no shock for the times of values V1, V2, V3, V4.

If at operation 2025 of FIG. 20 the answer is no, then execution mayproceed to operation 2018, in which case the next data that waslast-stored (value V3) become over-writable. Execution may then returnto operation 2010.

In the operating example for FIG. 20, the first time that operation 2025is performed is for values V2, and the answer is indeed no. Executionthen returns to operation 2016 for the third time. At that time, thenext data that was last-stored per operation 2066 was third values V3,and may become over-writable per operation 2018 as evidenced by theassociated dotted-lines square V3.

In the operating example for FIG. 20, during the third time thatoperation 2016 is performed, the next data that is stored in the memorycan be fourth values V4 that are derived from the fourth physiologicalinput made available due to operation 2010. Moreover, as these fourthvalues V4 become stored in the memory, at least some of the storedsecond values V2 do not become over-written by the storing of the fourthvalues V4. In fact, in some embodiments, none of the stored secondvalues V2 become over-written by the storing of the fourth values V4.Such over-writing is prevented due to operation 2019 having beenperformed, which is responsive to the cardiac arrhythmia having beendetected at operation 2017 in connection with the second values V2.

In addition, at least some of the stored third values V3 may optionallybecome over-written by the storing of the fourth values V4, responsiveto having determined that the detected cardiac arrhythmia is notvalidated at operation 2025. Such can become enabled if third values V3becomes over-writable, as per the above.

It will be appreciated that, in some such instances where the cardiacarrhythmia detected at values V2 does not meet the validation criterionper values V3, the speaker can be caused to output no sound at all, orno sound louder than 58 db, for another at least 10 min after thedetermination has been performed that the detected cardiac arrhythmiadoes not meet its validation criterion. This time can amount to a longquiet time for a cardiac arrhythmia that eventually self-terminated.

Sample results are now described. It will be recognized that theseresults correspond to the operating example for FIG. 20, but usedifferent embodiments for the memory configuration.

FIG. 22 shows a table whose first column shows values V1, V2, V3, V4described above, as they are being received or derived. For each ofthese values V1, V2, V3, V4 there is a row of results. In this example,according to the next column, an arrhythmia is detected for value V2,but not for values V1, V3, V4. In this example, according to the yetnext column, it is meaningful to validate the arrhythmia, only forvalues V2; and this arrhythmia is not validated because an arrhythmia isnot detected from the subsequent values V3, as shown by arrow 2225.

In the example of FIG. 22, according to the next column, there is noloud sound output responsive to any of values V1, V2, V3, V4. Accordingto a comment 2219, this is true even though value V2 had an arrhythmia,because that arrhythmia was not eventually validated.

In the example of FIG. 22, a memory 2238 of the WCD system according toembodiments could be memory 238. In the last column, an evolution isshown of a map of memory 2238, responsive to received values V1, V2, V3,V4 becoming stored. A previous value PV is stored longer-term, and isnot over-written. According to a comment 2219, values V2 are notoverwritten so as to be preserved for subsequent review, while valuesV1, V3, etc. are over-written in whole or in part by the subsequentlyreceived values, so as to conserve space in memory 2238.

In another example, FIG. 23 shows a table whose first four columns arethe same as those of FIG. 22. Values V2 do not meet the validationcriterion, because an arrhythmia is not detected from subsequent valuesV3, as shown by arrow 2325. According to a comment 2319, there is noloud sound output responsive to value V2, because its detectedarrhythmia was not eventually validated.

In the example of FIG. 23, a memory 2338 of the WCD system according toembodiments could be memory 238. Memory 2338 has a long term portion LTPand a short term portion STP. Second values V2 can be written in thelong term portion responsive to the cardiac arrhythmia having beendetected from the second physiological input. In fact, second values V2can be initially written in the short term portion, and then secondvalues V2 can become written to the long term portion by being copiedfrom the short term portion, responsive to the cardiac arrhythmia havingbeen detected from the second physiological input.

Similarly with FIG. 22, the last column of FIG. 23 shows an evolution ofa map of memory 2338, responsive to received values V1, V2, V3, V4becoming stored. A previous value PV is stored in the long term portion,and is thus not over-written. Incoming values V1, V2, V3, V4 are writtenin the short term portion, and then over-written by the subsequentlyincoming value, so as to conserve space. This short term portion may bea buffer that holds a time duration of data lasting for a suitable time,such as 2 minutes. Second values V2 can be copied in the long termportion from the short term portion, responsive to the cardiacarrhythmia having been detected from the second physiological input soas to be preserved for subsequent review, as shown by comment 2319.

The long-term stored values PV, V2 permit review of events, when thememory is downloaded later for study. In addition, for self-terminatingevents, the patient may have been spared the embarrassment of a loudalarm like a siren, if they do not respond quickly enough with thecancel switch, and so on.

FIG. 24 shows a flowchart 2400 for describing methods according toembodiments where data from self-terminating cardiac arrhythmias istransmitted by a WCD system without sounding loudly due to these cardiacarrhythmias. As with FIG. 17, flowchart 2400 can be performed for allpossible cardiac arrhythmias, or only certain types of ones.

In addition, FIG. 25 is a time diagram of a sample series of events thatmay result from methods of the flowchart of FIG. 24. Of course, from themethods of the flowchart of FIG. 24, a series of events may result thatis different than the sample series of events of FIG. 25. The events ofFIG. 25 are shown along a time axis 2512, with time intercepts that arenot to scale. This portion of this description proceeds by referring toboth FIGS. 24 & 25.

In FIG. 24, according to an operation 2410, physiological inputs from anECG signal of the patient are monitored. In FIG. 25, a timeline 2511indicates that the physiological input from the ECG starts beingreceived at a time T1, by switching from a low value to a high value.

In FIG. 24, an operation 2415 can be performed as described previouslyfor operations 415, 615, 715, 1715, etc. While at operation 2415 nocardiac arrhythmia is being detected, execution can return to operation2410. This detection or not of a cardiac arrhythmia is shown in FIG. 25along a timeline 2515. There is no detection while timeline 2515 has alow value. Detection may happen at time T2, at which time timeline 2515changes to a high value. At that time, detection may have been performedusing inputs received earlier.

It should be remembered that FIGS. 24, 25 are from the point of view ofthe WCD system, its processor, and so on. Accordingly, while a cardiacarrhythmia may be detected at time T2, the onset or first time point ofthe cardiac arrhythmia may be a little earlier and detection may besomewhat delayed. In the particular case of this example, a time line2514 shows a first time point of the cardiac arrhythmia as time TFTP,which is somewhat before time T2. (For example, in the prior art of FIG.3B, this first time point seems to occur at time TB.) In someembodiments, this first time point of the cardiac arrhythmia TFTP isidentified explicitly in the ECG signal.

Returning to FIG. 24, if detection happens at operation 2415, then therecan be waiting for up to a confirmation period to determine whether ornot the detected cardiac arrhythmia has self-terminated. This isexpressed in FIG. 24 as a waiting loop formed by operations 2419, 2422 &2472. It will be recognized that this waiting loop can be considered tobe a validation operation 2421, and that the confirmation period is atype of validation period.

In operation 2421, according to operation 2422, it is determined whetherthe confirmation period has passed. In some embodiments, theconfirmation period is defined as starting from a first time point ofthe cardiac arrhythmia, and lasting at least 35 sec, or longer, such as45 sec, 55 sec, etc. It will be appreciated that this confirmationperiod is substantially longer than the prior art of FIG. 3B and FIG.3C, thus giving a detected cardiac arrhythmia a better chance toself-terminate.

If at operation 2422 the answer is no, then there is waiting. During thewaiting, according to a next operation 2472 the speaker is caused tooutput no sound louder than 62 db, as measured at a distance of 2′ fromthe speaker. In some embodiments, the speaker is in fact caused tooutput no sound during this waiting, which means not a loud sound forbystanders, not an audible sound for the rescuer, etc.

According to a next operation 2419 it is determined whether or not thecardiac arrhythmia is still being detected from subsequent physiologicalinputs. If not, it means that the cardiac arrhythmia has self-terminatedwithin the confirmation period, and execution exits the waiting loop toreturn to operation 2410. In such embodiments, the discharge circuit canbe controlled to not cause a shock to be delivered responsive to thedetected cardiac arrhythmia.

It will be appreciated that, in some such instances where the detectedcardiac arrhythmia exits the waiting loop before the confirmationperiod, the speaker can be caused to output no sound at all, or no soundlouder than 58 db, for another at least 10 min after an end of theconfirmation period. This can amount to a long quiet time for a cardiacarrhythmia that eventually self-terminated.

If at operation 2419 the cardiac arrhythmia is still being detected,then execution proceeds again to operation 2422 of the waiting loop. Ifthe confirmation period has passed, then the cardiac arrhythmia has beenvalidated. Then, according to an operation 2440, the speaker can becaused to output a sound. In some embodiments, the sound is louder than50 db, as measured at a distance of 2′ from the speaker. In someinstances, audible sound is required to output verbal warnings to thewearer, for example at a sound intensity of a conversation, of perhapsaround 55 db at 2′. In some instances, loud sound is required, to outputa warning to bystanders that something extraordinary is going to happen.In such instances, that loud sound can be an alarm or even a siren, inwhich case it might be louder than 62 db as measured at a distance of 2′from the speaker. And, according to another operation 2499, thedischarge circuit can be controlled to cause the shock to be delivered.

In FIG. 25, the confirmation period is shown along a time line 2522,lasting between TFTP and T28. A decision diamond 2521 shows that, if yesand the cardiac arrhythmia is still detected, then there is a sound timeline 2542 showing a sound 2543, and a shock time line 2598 showing ashock 2599. Of course, sound 2543 can be an audible sound, a loud soundas per the above, etc.

If the answer to decision diamond 2521 is no, then there can be twobranches. In one branch 2519 while the cardiac arrhythmia is still beingdetected, then there is a loud sound time line 2572 showing no loudsound, and a shock time line 2588 showing no shock. These two time lines2572, 2588 could reach all the way to time T28 with no event while stillpart of the confirmation period; beyond time T28, however, they mightcontinue as time lines 2542, 2598 respectively.

If the answer to decision diamond 2521 is no, then there is anotherbranch 2571, where the cardiac arrhythmia is no longer being detected.Then then there is a loud sound time line 2570 showing no loud sound,and a shock time line 2597 showing no shock.

Additional embodiments may include what was described above withreference to additional speakers, and so on.

In the methods described above, each operation can be performed as anaffirmative step of doing, or causing to happen, what is written thatcan take place. Such doing or causing to happen can be by the wholesystem or device, or just one or more components of it. It will berecognized that the methods and the operations may be implemented in anumber of ways, including using systems, devices and implementationsdescribed above. In addition, the order of operations is not constrainedto what is shown, and different orders may be possible according todifferent embodiments. Examples of such alternate orderings may includeoverlapping, interleaved, interrupted, reordered, incremental,preparatory, supplemental, simultaneous, reverse, or other variantorderings, unless context dictates otherwise. Moreover, in certainembodiments, new operations may be added, or individual operations maybe modified or deleted. The added operations can be, for example, fromwhat is mentioned while primarily describing a different system,apparatus, device or method.

A person skilled in the art will be able to practice the presentinvention in view of this description, which is to be taken as a whole.Details have been included to provide a thorough understanding. In otherinstances, well-known aspects have not been described, in order to notobscure unnecessarily this description. Plus, any reference to any priorart in this description is not, and should not be taken as, anacknowledgement or any form of suggestion that such prior art formsparts of the common general knowledge in any country or any art.

This description includes one or more examples, but this fact does notlimit how the invention may be practiced. Indeed, examples, instances,versions or embodiments of the invention may be practiced according towhat is described, or yet differently, and also in conjunction withother present or future technologies. Other such embodiments includecombinations and sub-combinations of features described herein,including for example, embodiments that are equivalent to the following:providing or applying a feature in a different order than in a describedembodiment; extracting an individual feature from one embodiment andinserting such feature into another embodiment; removing one or morefeatures from an embodiment; or both removing a feature from anembodiment and adding a feature extracted from another embodiment, whileproviding the features incorporated in such combinations andsub-combinations.

In this document, the phrases “constructed to” and/or “configured to”denote one or more actual states of construction and/or configurationthat is fundamentally tied to physical characteristics of the element orfeature preceding these phrases and, as such, reach well beyond merelydescribing an intended use. Any such elements or features can beimplemented in a number of ways, as will be apparent to a person skilledin the art after reviewing the present disclosure, beyond any examplesshown in this document.

Any and all parent, grandparent, great-grandparent, etc. patentapplications, whether mentioned in this document or in an ApplicationData Sheet (“ADS”) of this patent application, are hereby incorporatedby reference herein as originally disclosed, including any priorityclaims made in those applications and any material incorporated byreference, to the extent such subject matter is not inconsistentherewith.

In this description a single reference numeral may be used consistentlyto denote a single item, aspect, component, or process. Moreover, afurther effort may have been made in the drafting of this description touse similar though not identical reference numerals to denote otherversions or embodiments of an item, aspect, component or process thatare identical or at least similar or related. Where made, such a furthereffort was not required, but was nevertheless made gratuitously so as toaccelerate comprehension by the reader. Even where made in thisdocument, such a further effort might not have been made completelyconsistently for all of the versions or embodiments that are madepossible by this description. Accordingly, the description controls indefining an item, aspect, component or process, rather than itsreference numeral. Any similarity in reference numerals may be used toinfer a similarity in the text, but not to confuse aspects where thetext or other context indicates otherwise.

The claims of this document define certain combinations andsubcombinations of elements, features and steps or operations, which areregarded as novel and non-obvious. Additional claims for other suchcombinations and subcombinations may be presented in this or a relateddocument. These claims are intended to encompass within their scope allchanges and modifications that are within the true spirit and scope ofthe subject matter described herein. The terms used herein, including inthe claims, are generally intended as “open” terms. For example, theterm “including” should be interpreted as “including but not limitedto,” the term “having” should be interpreted as “having at least,” etc.If a specific number is ascribed to a claim recitation, this number is aminimum but not a maximum unless stated otherwise. For example, where aclaim recites “a” component or “an” item, it means that it can have oneor more of this component or item.

1. A wearable cardioverter defibrillator (“WCD”) system, comprising: asupport structure configured to be worn by a patient; an energy storagemodule configured to store an electrical charge; a discharge circuitcoupled to the energy storage module, the discharge circuit controllableto discharge the stored electrical charge so as to cause a shock to bedelivered to the patient while the support structure is worn by thepatient; a measurement circuit configured to render physiological inputsfrom a physiological signal of the patient; a user interface thatincludes a speaker configured to output a sound; and a processorconfigured to: detect, from one of the physiological inputs, a cardiacarrhythmia of the patient, then determine whether or not the detectedcardiac arrhythmia meets a validation criterion, the determination beingperformed by a validation process that lasts for at least 25 sec, causethe speaker to output no sound louder than 58 db as measured at adistance of 2′ from the speaker while the determination being performed,and: if it is determined that the detected cardiac arrhythmia does notmeet the validation criterion, then control the discharge circuit to notcause a shock to be delivered to the patient responsive to the detectedcardiac arrhythmia, else cause the speaker to output a sound louder than62 db as measured at a distance of 2′ from the speaker, and control thedischarge circuit to cause the shock to be delivered.
 2. The WCD systemof claim 1, in which the physiological signal is an ElectroCardioGram(ECG) signal.
 3. The WCD system of claim 1, in which the cardiacarrhythmia is a ventricular tachycardia.
 4. The WCD system of claim 1,in which the determination of whether or not the detected cardiacarrhythmia meets the validation criterion is made from one of thephysiological inputs.
 5. The WCD system of claim 1, in which thevalidation process lasts for at least 35 sec.
 6. The WCD system of claim1, in which the speaker is caused to output no sound while thedetermination being performed.
 7. The WCD system of claim 1, in which ifit is determined that the detected cardiac arrhythmia does not meet thevalidation criterion, then the speaker is caused to output no soundlouder than 58 db as measured at a distance of 2′ from the speaker, foranother 10 min after the determination has been performed.
 8. The WCDsystem of claim 1, in which if it is determined that the detectedcardiac arrhythmia does not meet the validation criterion, then thespeaker is caused to output no sound, for another 10 min after thedetermination has been performed.
 9. The WCD system of claim 1, in whichthe user interface further includes an other speaker, and the otherspeaker is caused to output no sound louder than 58 db as measured at adistance of 2′ from the other speaker, while the determination beingperformed.
 10. The WCD system of claim 1, in which the user interfacefurther includes an other speaker, and the other speaker is caused tooutput no sound, while the determination being performed.
 11. Anon-transitory computer-readable storage medium storing one or moreprograms which, when executed by at least one processor of a wearablecardioverter defibrillator (“WCD”) system, the WCD system furtherincluding a support structure configured to be worn by a patient, anenergy storage module that can store an electrical charge, a dischargecircuit coupled to the energy storage module, a measurement circuitconfigured to render physiological inputs from a physiological signal ofthe patient, and a user interface that includes a speaker, these one ormore programs result in operations comprising: detecting, from one ofthe physiological inputs, a cardiac arrhythmia of the patient; thendetermining whether or not the detected cardiac arrhythmia meets avalidation criterion, the determination being performed by a validationprocess that lasts for at least 25 sec, causing the speaker to output nosound louder than 58 db as measured at a distance of 2′ from the speakerwhile the determination being performed; and: if it is determined thatthe detected cardiac arrhythmia does not meet the validation criterion,then controlling the discharge circuit to not discharge the storedelectrical charge through the patient responsive to the detected cardiacarrhythmia, else causing the speaker to output a sound louder than 62 dbas measured at a distance of 2′ from the speaker, and controlling thedischarge circuit to discharge the stored electrical charge through thepatient while the support structure is worn by the patient.
 12. Themedium of claim 11, in which the physiological signal is anElectroCardioGram (ECG) signal.
 13. The medium of claim 11, in which thecardiac arrhythmia is a ventricular tachycardia.
 14. The medium of claim11, in which the determination of whether or not the detected cardiacarrhythmia meets the validation criterion is made from one of thephysiological inputs.
 15. The medium of claim 11, in which thevalidation process lasts for at least 35 sec.
 16. The medium of claim11, in which the speaker is caused to output no sound while thedetermination being performed.
 17. The medium of claim 11, in which ifit is determined that the detected cardiac arrhythmia does not meet thevalidation criterion, then the speaker is caused to output no soundlouder than 58 db as measured at a distance of 2′ from the speaker, foranother 10 min after the determination has been performed.
 18. Themedium of claim 11, in which if it is determined that the detectedcardiac arrhythmia does not meet the validation criterion, then thespeaker is caused to output no sound, for another 10 min after thedetermination has been performed.
 19. The medium of claim 11, in whichthe user interface further includes an other speaker, and the otherspeaker is caused to output no sound louder than 58 db as measured at adistance of 2′ from the other speaker, while the determination beingperformed.
 20. The medium of claim 11, in which the user interfacefurther includes an other speaker, and the other speaker is caused tooutput no sound, while the determination being performed.
 21. A methodfor a wearable cardioverter defibrillator (“WCD”) system, the WCD systemincluding a support structure worn by a patient, an energy storagemodule that can store an electrical charge, a discharge circuit coupledto the energy storage module, a measurement circuit, a processor and auser interface that includes a speaker, the method comprising:rendering, by the measurement circuit physiological inputs from aphysiological signal of the patient; detecting, from one of thephysiological inputs, a cardiac arrhythmia of the patient; thendetermining whether or not the detected cardiac arrhythmia meets avalidation criterion, the determination being performed by a validationprocess that lasts for at least 25 sec; causing the speaker to output nosound louder than 58 db as measured at a distance of 2′ from the speakerwhile the determination being performed; and: if it is determined thatthe detected cardiac arrhythmia does not meet the validation criterion,then controlling the discharge circuit to not discharge the storedelectrical charge through the patient responsive to the detected cardiacarrhythmia, else causing the speaker to output a sound louder than 62 dbas measured at a distance of 2′ from the speaker, and discharging by thedischarge circuit the stored electrical charge through the patient whilethe support structure is worn by the patient.
 22. The method of claim21, in which the physiological signal is an ElectroCardioGram (ECG)signal.
 23. The method of claim 21, in which the cardiac arrhythmia is aventricular tachycardia.
 24. The method of claim 21, in which thedetermination of whether or not the detected cardiac arrhythmia meetsthe validation criterion is made from one of the physiological inputs.25. The method of claim 21, in which the validation process lasts for atleast 35 sec.
 26. The method of claim 21, in which the speaker is causedto output no sound while the determination being performed.
 27. Themethod of claim 21, in which if it is determined that the detectedcardiac arrhythmia does not meet the validation criterion, then thespeaker is caused to output no sound louder than 58 db as measured at adistance of 2′ from the speaker, for another 10 min after thedetermination has been performed.
 28. The method of claim 21, in whichif it is determined that the detected cardiac arrhythmia does not meetthe validation criterion, then the speaker is caused to output no sound,for another 10 min after the determination has been performed.
 29. Themethod of claim 21, in which the user interface further includes another speaker, and the other speaker is caused to output no sound louderthan 58 db as measured at a distance of 2′ from the other speaker, whilethe determination being performed.
 30. The method of claim 21, in whichthe user interface further includes an other speaker, and the otherspeaker is caused to output no sound, while the determination beingperformed. 31-159. (canceled)